Biomass-derived biofuels are central to reducing greenhouse gas (GHG) emissions and dependence on fossil fuels, yet large-scale deployment faces technical, economic, and environmental barriers. This review synthesizes advances in feedstock utilization, pretreatment methods, conversion pathways, hybrid systems, and policy frameworks shaping the biofuel landscape. First-generation crops such as corn and sugarcane yield 4000-7000 L/ha ethanol with limited pretreatment but compete with food supplies and consume 500-1000 L water per liter of ethanol. Second-generation residues (e.g., corn stover, switchgrass) achieve 280-300 L/ton ethanol and cut GHG emissions by 70%-90% (50-70 g CO2/MJ vs. 120-150 g CO2/MJ for fossil fuels). Third-generation microalgae produce 200-300 L/ton biocrude, though energy-intensive dewatering (10-15 MJ/kg) restricts feasibility. Pretreatment options-including physical (60%-70% sugar yield), chemical (90-95%), biological (50%-60%), and integrated systems (85%-95%)-enhance accessibility but remain costly ($0.05-10/kg). Conversion routes such as pyrolysis (70%-75% bio-oil), hydrothermal liquefaction (80%-85% efficiency), fermentation (280-300 L/ton ethanol), and anaerobic digestion (300-400 m3/ton biogas) offer versatile outputs, though bottlenecks like pentose fermentation losses persist. Integrated biorefineries and emerging platforms, including catalytic upgrading (80%-90% hydrocarbons) and bioelectrochemical systems (0.1-0.3 m3/m3/day H2), improve yields by 30%-50% but demand high capital costs ($100-200 million/plant). Policy interventions-such as renewable fuel standards (e.g., US RFS2) and carbon pricing ($50-100/ton CO2)-reduce costs by 10%-20% and boost production by 15%-25%, albeit with compliance challenges. Future priorities include cost-effective pretreatment, scalable biorefineries, durable catalysts, and AI-driven life cycle assessments to enable GHG reductions of 90-100 g CO2/MJ, positioning biofuels as a cornerstone of sustainable, low-carbon energy systems.
Currently, the increasing concentration of carbon dioxide (CO2) pollutants in the Earth's atmosphere due to the expansion of factories and vehicles has caused destructive effects, including an increase in the greenhouse effect, long-term droughts, insufficient rainfall, melting polar ice, and climate change. The various methods are available for removing carbon. Photocatalytic processes have emerged as promising and sustainable approaches for CO2 conversion because they don't make harmful byproducts, affect most contaminants, do not have any detrimental effects on the environment, don't need expensive, complicated equipment, are readily recoverable, recover, and use again. Perovskite is a novel kind of photocatalyst that exhibits excellent photocatalytic performance. Photocatalysts with more than one structure are better at covering a bigger area. Perovskite photocatalysts can reduce pollutants more quickly and better than other mono-photocatalysts. When exposed to visible light, this investigation intends to make a modern perovskite photocatalyst that exhibits enhanced performance and can convert carbon dioxide into solar fuels. To achieve this, g-C3N4 (gCN), a non-metallic co-photocatalyst; Bi2ZnTiO6 (BZTO), a double perovskite; and zero valent nickel/copper (Ni/Cu) nanoparticles, a metallic co-photocatalyst, were synthesized. XRD, SEM, EDX/mapping, UV-vis, DRS, and PL experiments were employed to look at the phase, crystallographic, structural, and photocatalytic properties. The performance of the Ni/Cu-loaded Bi2ZnTiO6 perovskite/g-C3N4 0D/3D/2D QDs Schottky/Z-scheme ternary heterojunction nanocomposite was optimized and improved using Taguchi's experimental design. The temperature of the reaction, how rapidly it was agitated, how long it took, how much CO2 and photocatalyst were present, visible irradiation intensity, interval between photoreduction site and light source, and the pH of the reaction are all critical parameters. To achieve the best conditions according to the Taguchi method, the solution should have a reaction medium pH of 5.0, a temperature of 25 °C, a mixing rate of 200 rpm, a photoreduction time of 300 min, a photocatalyst dosage of 1.0 g/l, a CO2 concentration of 400 mg L-1, a light intensity of 70 W, distance between light source and aqueous solution. The Ni/Cu-loaded Bi2ZnTiO6/g-C3N4 Schottky/Z-scheme ternary heterojunction nanocomposite transformed the CO2 with a proficiency rate of 1727 μmol g-1 h-1 (total CO2 conversion efficiency 95%) into the main solar fuels of methane (CH4) gas with a productivity ratio of 863.5 μmol g-1 h-1 (selectivity efficiency 50%) and methanol (CH3OH) with a productivity rate of 690.8 μmol g-1 h-1 (selectivity efficiency 40%). Additionally, the Ni/Cu-loaded Bi2ZnTiO6/g-C3N4 ternary nanocomposite maintained its structure and could be utilized over and over again, even after five cycles of continuous use.
Shifting the lens from the catalyst to the intrinsic physicochemical state of hazardous wastes, we unveil a macromolecular catalysis paradigm where the aging-induced modifications in polymer substrates dictate their catalytic hydrogenolysis pathways. By harnessing sunlight as a powerful engine, photo-aging process implants the signature alterations of "oxygenated functional groups, microcracks, and chain crosslinks" into polyolefins, creating specific weak links that reprogram their upcycling selectivity. With a tailored urchin-like Ru/CeO2 catalyst, we demonstrate divergent product streams from laboratory photoaged plastics: air-aged polyethylene yields narrow-distribution wax with a melting range of 94.7-101.8 °C (PDI = 1.64), whereas wet-aged polyethylene produces a liquid alkane stream (C5-C17) rich in fuel-range hydrocarbons. This pathway divergence extends to the hydrogenolysis of polystyrene, where aged plastics upgrades into potential aviation-fuel components of aliphatic alkanes and saturated cycloalkanes. Compared with the pristine plastics, the photo-aged microplastics were for the first time transformed from an emerging global hazard into a sustainable source for high-value fuels and chemicals.
The effective photoreforming of polylactic acid (PLA) critically depends on the regulation of reactive oxygen species (ROS). Conventional pathways dominated by hydroxyl radicals suffer from short lifetimes and uncontrolled mineralization. Herein, we report the first realization of direct PLA photoreforming under ambient conditions exclusively mediated by superoxide radicals (•O2-), establishing a new pathway for selective bond scission and carbon-conserving upcycling. Such control is enabled by deliberately designed Au-TiO2 heterostructures, which form Schottky junctions and charge-transfer channels. Au serves as an electron reservoir, while TiO2 provides a robust scaffold sustaining carrier dynamics, together allowing the generation and stabilization of •O2-. Nucleophilic •O2- radicals induce Cα-H activation in PLA, which lowers the energetic disparity between C-C and C-O cleavage, thus eliminating the inherent bias toward ester cleavage and allowing C-C bond cleavage. As a result, carbon is funneled into liquid fuels, yielding acetic acid at 5.72 mmol g-1 with 71.3% liquid product selectivity and maintaining stable activity for over one week under simulated solar irradiation. Interfacial single-electron transfer is thereby identified as a governing principle for ROS control, providing a direct and carbon-efficient route for the upcycling of PLA into liquid fuels.
Efficiently valorizing mixed oxygenated aromatic plastic waste into high-value chemicals remains a major challenge in sustainable waste management. Hydrodeoxygenation (HDO) is a promising strategy, but conventional catalysts often lead to complex product mixtures due to undesired C-C bond cleavage and isomerization. Here, we report a stepwise HDO strategy over a Rh/Nb2O5 catalyst that enables the selective and sequential conversion of mixed oxygenated aromatic plastics into well-defined cycloalkane products. This process achieves remarkable 92.3% yields of 1,1'-(1-methylethylidene)biscyclohexane (a C15 cycloalkane suitable as an additive for aviation and jet fuels) and 86.1% yields of C6-C8 cycloalkanes for gasoline, from mixed feedstocks including polycarbonate (PC), poly(phenylene oxide) (PPO), polyethylene terephthalate (PET), and polybutylene terephthalate (PBT). Mechanistic investigations reveal that the catalyst's abundant Lewis acid sites, minimal Brønsted acidity, and strong affinity for aromatic and oxygenated groups synergistically enable sequential C═C hydrogenation and selective C-O bond hydrogenolysis, while effectively suppressing C-C bond cleavage. The system exhibits excellent tolerance to contaminants in real-world plastic wastes, supporting its practical applicability. Techno-economic and life cycle assessments further confirm the environmental and economic viability of the process. This work provides a general strategy for precision upcycling of complex plastic mixtures into fuel-range cycloalkanes and offers design principles for catalytic control of oxygenated polymer valorization toward circular plastic economies.
The examination of building materials for natural radioactivity to comply with legal regulations is a standard procedure in all European countries. This paper presents the results of measurements conducted in recent years at our laboratory within ISO 17025 - accredited procedure. The vast majority of the results meet the accepted activity- concentration requirement. However, due to the mandatory use of bio-fuels, some building materials showed the presence of 137Cs in addition to natural radionuclides. The presence of an artificial radionuclide is a new feature for mineral-base building materials.
Emerging evidence highlights that metabolic reprogramming profoundly shapes the tumor microenvironment and immune evasion in prostate cancer. However, the functional role and mechanisms of tryptophan metabolism in prostate cancer progression remain unclear. Through single-cell transcriptomic analysis, we identified one tumor cell subtype characterized by high expression of 3-hydroxyanthranilate 3,4-dioxygenase (HAAO) and enhanced kynurenine pathway activity. This subpopulation leads to the accumulation of quinolinic acid (QA), a metabolic intermediate that could activate the mevalonate (MVA) pathway. Mechanistically, QA directly binds to and stabilizes farnesyl diphosphate synthase (FDPS), a key MVA pathway enzyme, thereby enhancing cholesterol biosynthesis and fueling androgen receptor (AR)-driven transcriptional programs. This HAAO/QA-FDPS axis establishes a metabolic crosstalk that links tryptophan catabolism to lipid metabolism, sustaining prostate tumor progression. Furthermore, an integrated prognostic model incorporating this pathway signatures outperforms other clinical variables alone, and HAAO-high tumors exhibit heightened sensitivity to combined inhibition of the kynurenine and AR pathways. Our study unveils a novel metabolic vulnerability in prostate cancer and provides a mechanistic rationale for targeting the HAAO/QA-FDPS axis for therapy.
Dimethyl sulfate (DMS), (CH3)2SO4, is a highly toxic industrial chemical. Upon contact with moist mucosa, it hydrolyzes into sulfuric acid and methanol, causing severe corrosive damage to the eyes and respiratory tract. While its acute toxicity is well known, factors that may modify the severity of poisoning remain unreported. In particular, the potential interaction between alcohol consumption and DMS toxicity has not been previously described. We present three patients with acute DMS vapor poisoning following occupational exposure. Notably, two patients consumed approximately 100 mL of 53% vol liquor (baijiu) after exposure and experienced a marked exacerbation of ocular pain, photophobia, corneal epithelial defects, and respiratory symptoms. In contrast, the third patient, who did not drink alcohol, had initially similar or even more severe symptoms but showed a faster and more stable recovery without exacerbation. This clinical divergence strongly suggests that ethanol intake amplified the chemical injury, likely through proinflammatory and metabolic pathways. Alcohol consumption may worsen DMS poisoning and delay recovery. Clinicians should advise patients with known or suspected DMS exposure to avoid alcohol. This recommendation should be integrated into discharge instructions and occupational safety protocols. Further studies are needed to clarify the underlying mechanisms and to confirm this clinically relevant interaction.
Wounding triggers growth programs to restore damaged tissues, creating a local surge in metabolic demand. How resource recruitment is modified to meet this demand is unclear. Here, we show that regeneration of dissected root tips is dependent on photosynthetic sucrose in a dose-dependent manner, although sucrose itself is excluded from the injury site. High-resolution tracking of Glifon, a live glucose reporter, reveals that glucose accumulates near the cut. Glucose accumulation required the apoplasmic sugar transport components CELL WALL INVERTASE (CWINV) and SUGAR TRANSPORTER PROTEINS (STP), which were rapidly induced by wounding. Loss of CWINV or STP function compromised root repair, particularly under limited sucrose availability, whereas increased STP13 gene dosage enhanced repair rates. Similar sugar transport genes were activated in other wounding contexts and promoted wound-induced adventitious root initiation. We propose that injury elicits a proactive local shift in sugar flow to promote resource recruitment and sustain tissue repair.
Octane numbers (ON) and derived cetane numbers (DCN) are widely used as indicators to quantify the ignition qualities of gasoline- and diesel-type fuels, respectively. In this study, a chemical kinetics-based methodology is proposed for quantitatively relating ignition delay times (IDTs) to the ON and subsequently deriving correlations to predict DCN. The methodology is based on the ignition-delay-time equivalence principle, according to which fuels exhibiting ignition delay times identical to those of primary reference fuel (PRF) mixtures under well-defined RON-like thermodynamic conditions are assigned the same octane number. To assess the predictive capability of this methodology, ignition delay times of both test fuels and PRF mixtures were simulated under RON-like conditions using detailed chemical kinetic mechanisms for toluene primary reference fuels (TPRF) developed independently by various research groups. The predicted ON values were validated against experimentally measured ON data obtained using standard ASTM methods. For PRF, TRF, and TPRF blends under RON-like conditions over 30-80 bar at φ = 1.0, the best overall correlation was achieved at 40 bar, with an R2 of 0.988 and an RMSE of 1.322. The validation results confirm that the proposed kinetic modeling approach provides reliable and accurate predictions of ON, with improved accuracy correlating closely with the precision of simulated ignition delay times. Subsequently, a linear correlation between the predicted ON and DCN values, measured in accordance with ASTM D6890 standards, was established. The predicted DCN values exhibit satisfactory agreement with experimental data under the specified RON-like conditions. The developed kinetic-based methodology provides valuable theoretical insights for engine design and operation, as well as the development of future fuels.
Traffic and transportation are the sources of pollution in roadside soil-groundwater systems by petroleum products and heavy metals. In this study, geotextile systems were used as adsorption layers for petroleum substances and heavy metals in a pilot scale test that simulates runoff from the petroleum station and roads under moderate and heavy rainfall. Two new types of geotextiles filled with (1) activated carbon and (2) composite mineral sorbent consisted of halloysite, recycled rubber and fly ash were used. Geotextiles were installed in the base layer below the pavement. Diesel oil, E95 petrol, motor oil, zinc and copper were dosed on the pavement under routine and accidental leak scenarios. The performance of the geotextiles was assessed on pollutant concentrations measured in the outflow from the column system. Despite the high cumulative load of fuels (diesel oil and E95 petrol, each 2x180 g/m2), copper (500 mg/m2) and zinc (500 mg/m2) applied during the routine leakage test, the concentrations of copper and zinc from petroleum products in the outflow did not exceed 1.3 mg/L 0.9 mg/L, and 0.24 mg/L, respectively. The geotextiles also effectively trapped petroleum products during simulations of large accidental spill events. Despite substantial loads of spilt fuels (948 g/m2) and motor oil (1044 g/m2), the concentration of petroleum products in the outlet remained below 0.26 mg/L and 0.31 mg/L, respectively. Petroleum products originating from motor oil were retained more effectively by the geotextile containing the mineral sorbent, whereas petroleum products from fuels were more efficiently adsorbed by the geotextile-activated carbon system. This was because smaller fuel molecules more easily penetrating the microporous structure of activated carbon was more easily adsorbed, while motor oil-characterised by higher viscosity and larger particle size-was more effectively adsorbed by the mineral sorbent with a mesoporous structure.
In recent years, the worsened environmental impacts and the limited reserve of fossil fuels have increased interest in alternative fuels. Fuels obtained by recycling waste streams, such as waste tires and transformer oils, are promising options. Pyrolytic oil from end-of-life waste tires is not an alternative for diesel engines on its own, but its fuel blends with diesel in different proportions enable its use in diesel engines without any modification. Furthermore, transformer oils used as heat-transfer fluids in electrical transformers reach the end of their useful life after completing a certain number of cycles and become waste. This waste stream can also be used to blend diesel fuel. In this study, waste transformer oil (WTRO) and pyrolytic oil from waste tires (WTPO) were mixed with diesel fuel in different ratios to prepare binary and ternary blends: WTRO30, WTRO10WTPO20, WTRO20WTPO10, and WTPO30. The performance and emissions of these fuel blends were investigated on a diesel engine. To avoid knocking, a cetane-number improver was added to all blends at a volume ratio of 1%. In addition, detailed analyses of certain physicochemical and thermochemical properties (FT-IR, density, kinematic viscosity, cloud point, pour point, and lower heating value) of all blends were performed. The results of the study showed that the chemical properties of the prepared blends exhibited similar results to diesel fuel. When compared with pure diesel data, the most significant performance loss across all speed ranges was observed in the WTPO30 fuel sample. The use of WTPO30 resulted in a noticeable decrease in maximum torque and a brake power while recording the highest brake specific fuel consumption and lowest brake thermal efficiency. Furthermore, significant increases in CO, NO, and NO x emissions were observed. The results of the study revealed striking findings regarding the use of WTPO and WTRO in diesel engines.
Increased atmospheric carbon dioxide (CO2) emissions in the atmosphere due to excessive usage of fossil fuels, rapid industrial development and human growth have raised a global interest in the greenhouse effect. CO2 conversion is important not just because it is a greenhouse gas that causes a variety of climate consequences, but also because it is the most abundant source of valuable organic chemicals. Upgrading CO2 into valuable chemicals and materials offers a pathway toward net-zero or even carbon-negative production of fuels, pharmaceuticals, alcohols, plastics, etc. However, current CO2 conversion technologies have the problems of high operational costs, high energy consumption, limited to a few-carbon products, and a risk of secondary pollutants. Microbial electrosynthesis (MES) is a novel microbial electrochemical technology that integrates the metabolic activities or genetic behaviour of microorganisms on electrodes to convert CO2 into organics with electrical energy input. Recent developments in electrode and reactor design, synthetic biology-based strain engineering, and genetic engineering have enhanced the production rates and selectivity of MES. This review explores the transformative potential and recent progress of MES with CO2 upgrading strategies, aiming to identify the determinants of the process and its future research directions.It also highlights the current challenges of MES related to upscaling, long-term stability, selecting optimal microbial strains, achieving net-negative carbon emissions, and other operational limitations that need to be addressed for commercial viability.
The transition toward a carbon-neutral energy system requires efficient strategies to convert CO2 into energy-dense liquid fuels capable of decarbonizing sectors where electrification remains impractical. Among emerging renewable synthetic fuels, ethanol is particularly attractive due to its high energy density, favorable handling properties, chemical versatility, and compatibility with existing infrastructure. Thermocatalytic and photocatalytic CO2 conversion routes have advanced rapidly, yet challenges in activity, selectivity, and catalytic durability continue to limit large-scale deployment. This review surveys catalytic systems developed for CO2-to-ethanol conversion, covering both thermocatalytic and light-driven approaches. Proposed reaction mechanisms are discussed with emphasis on how CC coupling pathways depend on alloying, promoter effects, support properties, tandem configurations, and semiconductor design. Catalyst performance is compared across studies, and systems are grouped according to metal abundance and prevalence, highlighting strategies that enhance ethanol selectivity and productivity. Overall, this review integrates experimental performance with mechanistic insights from spectroscopy and theory, provides a comprehensive overview of the state of the art, and identifies key challenges and future directions for achieving higher yields, improved selectivity, and long-term stability in renewable ethanol production from captured CO2.
Volatile substance abuse (VSA) continues to cause preventable deaths worldwide. In Australia, petrol sniffing has historically been the main form of misuse in remote Indigenous communities. However, coronial and surveillance data suggest an increasing role of gas fuels and aerosol propellants. Twenty-five VSA-related deaths reported to the Northern Territory (NT) coroner over a 21-year period (2002-2022) were reviewed. In the 22 cases where acute volatile substance inhalation was the direct cause of death, the decedents were all male, and predominantly young Aboriginal individuals aged between 12 and 29 years. Furthermore, petrol vapor inhalation was responsible for most fatalities up to 2018, after which no further petrol sniffing-related deaths occurred. Deaths that occurred after 2018 were associated with the use of propane or butane from aerosol cans, such as those used for deodorants. A public health initiative that resulted from this was the keeping of aerosol deodorants in supermarkets within locked cabinets. In conclusion, public health interventions, such as the introduction of Opal fuel in remote communities in the NT, have been effective, with a sharp decrease in petrol sniffing-related fatalities. However, this seemed to have led to a shift towards the use of other inhalants, most commonly butane and/or propane inhaled from aerosol canisters. Forensic practitioners should be alert to non-petrol volatiles, and public health strategies need to broaden beyond petrol substitution to include regulatory and community-level measures addressing gas fuels and aerosols.
Incineration remains a common method for healthcare waste disposal; however, concerns related to air pollutant emissions, limited resource recovery, and compatibility with circular economy goals have driven interest in alternative treatment technologies. Among thermochemical options, pyrolysis offers advantages over incineration by operating under oxygen-limited conditions, enabling conversion of waste into value-added products while potentially reducing the formation of regulated air pollutants. This review examines the state of pyrolytic valorization of healthcare waste and its potential role within sustainable waste management systems and circular economy. A brief bibliometric assessment indicates that although pyrolysis research has traditionally focused on biomass and municipal solid waste, studies addressing healthcare waste have increased steadily in recent years. Different categories of healthcare-related wastes, including hospital residues and medical plastics, are reviewed alongside applicable pyrolysis reactor technologies. The properties and potential uses of resulting products, including syngas, liquid fuels, waxes, and chemical feedstocks, are discussed in relation to environmental performance and resource recovery. Key challenges, such as feedstock heterogeneity, contaminant management, regulatory constraints, and process optimization, are identified. Overall, pyrolysis is presented as a complementary technology that can support circular economy objectives in healthcare waste management.Implications: Incineration remains widely used for healthcare waste disposal, but concerns regarding emissions, limited resource recovery, and circular economy compatibility have increased interest in pyrolysis. This review evaluates pyrolytic valorization of healthcare waste as a sustainable complementary technology to incineration. Different healthcare waste streams, reactor technologies, operating conditions, and resulting products, including syngas, liquid fuels, waxes, and chemical feedstocks, are discussed. Key challenges such as feedstock heterogeneity, contaminant management, regulatory limitations, and process optimization are highlighted. Essentially, pyrolysis demonstrates significant potential for resource recovery and sustainable healthcare waste management within circular economy frameworks.
Methane (CH4), as both a carbon resource and greenhouse gas, requires an effective and ecologically friendly catalysis to accomplish the conversion into valued-added chemicals or fuels, wherein the establishment of a proper multi-site active structure to boost the C─H dissociation and C─C coupling demands further exploration. Herein, we disclose a facile and general approach by controlling the electronic property of Ni to preserve a moderate orbital hybridization (d-p) with O, and thereby induce a synergistic Ni─O dual-site for the expected electrocatalysis of CH4 toward C2 product. Specifically, along the d band shifting downwards via the Ni valence increase, the optimal NiOOH not only affords sufficient capability for the CH4 oxygenation relative to the Ni(OH)2, but also minimizes the probability of O detachment compared with the NiO2. The resultant NiOOH catalyst exhibits the highest Faradaic efficiency of 53.5% with a production rate of 401.6 µmol gcat. -1 h-1 or 1.61 µmol h‒1 cm‒2 for acetic acid, and a long-term stability for over 50 h without detectable structural deterioration. This study develops an efficient electrocatalytic CH4 process, and could arouse extensive attention to the new materials and routes meeting the economicity and sustainability.
Mimicking natural photosynthesis to split water into oxygen and hydrogen represents a promising pathway for transitioning from fossil fuels to a sustainable energy future. It is extremely challenging to duplicate the efficient and elegant oxygen evolution complex of photosynthesis II of oxidizing water to O2 being regarded as the bottleneck of water splitting. Cutting-edge artificial molecular water oxidation catalysts (WOCs) with low overpotentials are highly desirable for efficient water oxidation. Here we report the design of a molecular water oxidation catalyst (WOC) RuN5 (Ru(N5)(pic)2; N5 = 4-tert-butyl-2,6-di(1',8'-naphthyrid-2'-yl)pyridine, pic = 4-picoline). Following electrochemical activation and bromide mediation, RuN5 achieves a high turnover frequency of 2604 s-1 with a low overpotential of 363 mV at pH 7. The catalyst is highly stable, maintaining a steady current density of 1.8 mA cm-2 over 200 h. Mechanistic studies reveal that activation and bromide mediation facilitate O-O bond formation via a ligand-oxidized [RuIV═O]2+ intermediate through a low energy pathway, distinct from the classical [RuV(O)]3+ route. This work opens a new avenue for developing efficient molecular WOCs and advancing artificial photosynthesis.
Single-atom catalysts (SACs) have emerged as highly versatile catalytic materials for enhancing many industrially relevant electrochemical reactions. This review highlights recent advancements in the development of iridium SACs, primarily for water splitting applications. By reducing iridium to the single atom scale, the inherent beneficial scaling relationships can be preserved while substantially reducing precious metal loading to achieve mass activity as high as 2511 A gIr-1. The single-atom character also allows for unique electronic and coordination interactions, resulting in oxidation states surpassing Ir(V) and enhancement of the lattice oxygen implementation, expanding the parameters for electrochemical performance optimization. Through this optimization, one highlighted catalyst was able to achieve an overpotential of 144 mV at 10 mA cm-2 for the oxygen evolution reaction, resulting in hydrogen generation surpassing the Department of Energy targets. Although currently limited by synthetic obstacles, the recent advances in Ir SACs highlighted in this review aim to show potential pathways towards commercial applications, contributing to the widespread implementation of zero emission hydrogen fuels.
Optimizing the surface-interface structure and electronic interactions of palladium-based materials is crucial for accelerating the electro-oxidation of liquid fuels; However, the sluggish kinetics and complicated oxidation process still pose formidable challenges for their application in fuel cells. Herein, we fabricated defect-rich Pd2Pb3Zn4 (D-Pd2Pb3Zn4) intermetallic compound featuring nanonetwork structure. Notably, the introduction of plumbum (Pb) element promotes the generation of an ordered palladium-based alloy, whereas the leaching of zinc (Zn) element is crucial for the creation of defects. This catalyst features a highly open structure, strong electronic effect, and sufficient active sites, demonstrating remarkable electrocatalytic activity and excellent durability for ethylene glycol oxidation reaction (EGOR) in alkaline electrolyte. Impressively, the mass activity of the D-Pd2Pb3Zn4/C electrocatalytic EGOR is as high as 11.9 A mgPd-1, which is 1.2 and 9.0-fold higher than that of the Pd2Pb3Zn4/C (9.86 A mgPd-1) and Pd/C (1.32 A mgPd-1) catalysts, respectively. Kinetic and thermodynamic analyses reveal that the D-Pd2Pb3Zn4/C catalyst is superior to the Pd2Pb3Zn4/C catalyst in terms of facilitating mass transfer, reducing the electrochemical activation energy, enhancing electronic conductivity, accelerating charge transfer, improving the resistance to CO poisoning, and maintaining satisfactory long-term stability. Meanwhile, in-situ fourier transform infrared (FTIR) spectrum confirmed that the D-Pd2Pb3Zn4/C enhances the selectivity toward C1 products from ethylene glycol oxidation as compared to the Pd2Pb3Zn4/C catalyst, with an optimal selectivity of 42.7% that underscores its superior CC bond cleavage ability. This study not only provides an effective synthetic strategy for preparing Pd-based nanomaterials with defective and ordered structures, but also has important guiding significance for optimizing EGOR via the C1 pathway.