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Isolated Fe-N x sites coupled with Fe 3 C nanoparticles co-embedded in N-doped porous carbon were fabricated using polyethylene terephthalate wastes as carbon sources. Benefiting from the synergistic effect between Fe-N x sites and Fe 3 C, and the hierarchical porous structure, the catalyst exhibits outstanding ORR performance, realizing the concept of turning trash into treasure.

The electrochemical conversion of glycerol into high-value chemicals through the selective glycerol oxidation reaction (GOR) holds importance in utilizing the surplus platform chemical component of glycerol. Nevertheless, it is still very limited in producing three-carbon chain (C 3 ) chemicals, especially glyceric acid/glycerate, through the direct oxidation of its primary hydroxyl group. Herein, Pd microstructure electrodeposited on the Ni foam support (Pd/NF) is designed and fabricated to achieve a highly efficient GOR, exhibiting a superior current density of ca. 120 mA cm -2 at 0.8 V vs. reversible hydrogen electrode (RHE), and high selectivity of glycerate at ca. 70%. The Faradaic efficiency of C 3 chemicals from GOR can still be maintained at ca. 80% after 20 continuous electrolysis runs, and the conversion rate of glycerol can reach 95% after 10-h electrolysis. It is also clarified that the dual-component interfaces constructed by the adjacent Pd and Ni sites are responsible for this highly efficient GOR. Specifically, Ni sites can effectively strengthen the generative capacity of the active adsorbed hydroxyl (OH ad ) species, which can steadily immigrate to the Pd sites, so that the surface adsorbed glycerol species are quickly oxidized into C 3 chemicals, rather than breaking the C-C bond of glycerol; thus, neither form the C 2 /C 1 species. This study may yield fresh perspectives on the electrocatalytic conversion of glycerol into high-value C 3 chemicals, such as glyceric acid/glycerate.

Ethylene glycol (EG) is one of the most attractive platform molecules derived from biomass and waste plastics. Thus, the selective electrooxidation of ethylene glycol (EGOR) into value-added chemicals (especially glycolic acid (GA)) can promote its recycling and upgrading. However, the understanding of the EG-to-GA process on Pt-group metal (PGM) electrodes is far limited now. It has been shown that the Pt and Pd electrodes could show considerable EGOR activity but not Rh and Ir electrodes. Meanwhile, EGOR mainly produces the glycolate, oxalate, and formate on Pt and Pd electrodes, whereas it can obtain minute amounts of glycolate and oxalate on Rh and Ir electrodes. Impressively, the selectivity of glycolate on Pt and Pd electrodes can be over 85% (apparent Faradaic efficiency) in alkaline media, although the stability should be further improved through interfacial tuning and/or engineering. This work might deepen the fundamental understanding of the EGOR process on the nature of PGM electrodes.

Metallic lithium (Li) is highly desirable for Li battery anodes due to its unique advantages. However, the growth of Li dendrites poses challenges for commercialization. To address this issue, researchers have proposed various three-dimensional (3D) current collectors. In this study, the selective modification of a 3D Cu foam scaffold with lithiophilic elements was explored to induce controlled Li deposition. The Cu foam was selectively modified with Ag and Sn to create uniform Cu foam (U-Cu) and gradient lithiophilic Cu foam (G-Cu) structures. Density Functional Theory (DFT) calculations revealed that Ag exhibited a stronger binding energy with Li compared to Sn, indicating superior Li induction capabilities. Electrochemical testing demonstrated that the half cell with the G-Cu@Ag electrode exhibited excellent cycling stability, maintaining 550 cycles with an average Coulombic efficiency (CE) of 97.35%. This performance surpassed that of both Cu foam and G-Cu@Sn. The gradient modification of the current collectors improved the utilization of the 3D scaffold and prevented Li accumulation at the top of the scaffold. Overall, the selective modification of the 3D Cu foam scaffold with lithiophilic elements, particularly Ag, offers promising prospects for mitigating Li dendrite growth and enhancing the performance of Li batteries., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

The electrochemical conversion of CO 2 into multicarbon (C 2 ) products on Cu-based catalysts is strongly affected by the surface coverage of adsorbed CO (*CO) intermediates and the subsequent C-C coupling. However, the increased *CO coverage inevitably leads to strong *CO repulsion and a reduced C-C coupling efficiency, thus resulting in suboptimal CO 2 -to-C 2 activity and selectivity, especially at ampere-level electrolysis current densities. Herein, we developed an atomically ordered Cu 9 Ga 4 intermetallic compound consisting of Cu square-like binding sites interspaced by catalytically inert Ga atoms. Compared to Cu(100) previously known with a high C 2 selectivity, the Ga-spaced, square-like Cu sites presented an elongated Cu-Cu distance that allowed to reduce *CO repulsion and increased *CO coverage simultaneously, thus endowing more efficient C-C coupling to C 2 products than Cu(100) and Cu(111). The Cu 9 Ga 4 catalyst exhibited an outstanding CO 2 -to-C 2 electroreduction, with a peak C 2 partial current density of 1207 mA cm -2 and a corresponding Faradaic efficiency of 71%. Moreover, the Cu 9 Ga 4 catalyst demonstrated a high-power (∼200 W) electrolysis capability with excellent electrochemical stability.

Advancing the performance of the Cu-catalyzed electrochemical CO 2 reduction reaction (CO 2 RR) is crucial for its practical applications. Still, the wettable pristine Cu surface often suffers from low exposure to CO 2 , reducing the Faradaic efficiencies (FEs) and current densities for multi-carbon (C 2+ ) products. Recent studies have proposed that increasing surface availability for CO 2 by cation-exchange ionomers can enhance the C 2+ product formation rates. However, due to the rapid formation and consumption of *CO, such promotion in reaction kinetics can shorten the residence of *CO whose adsorption determines C 2+ selectivity, and thus the resulting C 2+ FEs remain low. Herein, we discover that the electro-kinetic retardation caused by the strong hydrophobicity of quaternary ammonium group-functionalized polynorbornene ionomers can greatly prolong the *CO residence on Cu. This unconventional electro-kinetic effect is demonstrated by the increased Tafel slopes and the decreased sensitivity of *CO coverage change to potentials. As a result, the strongly hydrophobic Cu electrodes exhibit C 2+ Faradaic efficiencies of ≈90 % at a partial current density of 223 mA cm -2 , more than twice of bare or hydrophilic Cu surfaces., (© 2023 Wiley-VCH GmbH.)

The reasonable design of atomically dispersed Ni-N x sites in porous carbon nanostructures is an efficient strategy to enhance the electrochemical CO 2 reduction reaction (CO 2 RR) catalytic activity. In this work, atomically dispersed Ni-N x sites on hierarchically porous carbon catalysts (HP-Ni-NC) were fabricated by a facile NaCl template-assisted pyrolysis method. The catalysts exhibit a large specific surface area and a hierarchical porous structure, facilitating the exposure of numerous active sites and the mass/electron transport during the CO 2 RR. Consequently, the CO Faradaic efficiency maintained over 90% in a wide potential window on the optimized HP-Ni-NC-2 catalyst. The CO partial current achieved 15.2 mA cm -2 at -0.9 V (vs reversible hydrogen electrode) in a H-cell. Furthermore, the current density can achieve 250 mA cm -2 at a cell voltage of 3.11 V in a membrane electrode assembly electrolyzer, demonstrating great promise for commercial-scale application. This study presents a facile approach to synthesizing hierarchically porous structure single-atom catalysts with superior catalytic performance toward CO 2 RR.

There is an urgent need for cost-effective strategies to produce hydrogen from renewable net-zero carbon sources using renewable energies. In this context, the electrochemical hydrogen evolution reaction can be boosted by replacing the oxygen evolution reaction with the oxidation of small organic molecules, such as ethylene glycol (EG). EG is a particularly interesting organic liquid with two hydroxyl groups that can be transformed into a variety of C1 and C2 chemicals, depending on the catalyst and reaction conditions. Here, a catalyst is demonstrated for the selective EG oxidation reaction (EGOR) to formate on nickel selenide. The catalyst nanoparticle (NP) morphology and crystallographic phase are tuned to maximize its performance. The optimized NiS electrocatalyst requires just 1.395 V to drive a current density of 50 mA cm -2 in 1 m potassium hydroxide (KOH) and 1 m EG. A combination of in situ electrochemical infrared absorption spectroscopy (IRAS) to monitor the electrocatalytic process and ex situ analysis of the electrolyte composition shows the main EGOR product is formate, with a Faradaic efficiency above 80%. Additionally, C2 chemicals such as glycolate and oxalate are detected and quantified as minor products. Density functional theory (DFT) calculations of the reaction process show the glycol-to-oxalate pathway to be favored via the glycolate formation, where the CC bond is broken and further electro-oxidized to formate., (© 2023 The Authors. Advanced Science published by Wiley-VCH GmbH.)

While tuning the electronic structure of Pt can thermodynamically alleviate CO poisoning in direct methanol fuel cells, the impact of interactions between intermediates on the reaction pathway is seldom studied. Herein, we contrive a PtBi model catalyst and realize a complete inhibition of the CO pathway and concurrent enhancement of the formate pathway in the alkaline methanol electrooxidation. The key role of Bi is enriching OH adsorbates (OH ad ) on the catalyst surface. The competitive adsorption of CO adsorbates (CO ad ) and OH ad at Pt sites, complementing the thermodynamic contribution from alloying Bi with Pt, switches the intermediate from CO ad to formate that circumvents CO poisoning. Hence, 8% Bi brings an approximately 6-fold increase in activity compared to pure Pt nanoparticles. This notion can be generalized to modify commercially available Pt/C catalysts by a microwave-assisted method, offering opportunities for the design and practical production of CO-tolerance electrocatalysts in an industrial setting.

Although many catalysts have been reported for the CO 2 electroreduction to C 1 or C 2 chemicals, the insufficient understanding of fundamental correlations among different products still hinders the development of universal catalyst design strategies. Herein, we first discover that the surface *CO coverage is stable over a wide potential range and reveal a linear correlation between the partial current densities of CH 4 and C 2 products in this potential range, also supported by the theoretical kinetic analysis. Based on the mechanism that *CHO is the common intermediate in the formation of both CH 4 (*CHO → CH 4 ) and C 2 (*CHO + *CO → C 2 ), we then unravel that this linear correlation is universal and the slope can be varied by tuning the surface *H or *CO coverage to promote the selectivity of CH 4 or C 2 products, respectively. As proofs-of-concept, using carbon-coated Cu particles, the surface *H coverage can be increased to enhance CH 4 production, presenting a high CO 2 -to-CH 4 Faradaic efficiency ( [Formula: see text] ∼52%) and an outstanding CH 4 partial current density of -337 mA cm -2 . On the other hand, using an Ag-doped Cu catalyst, the CO 2 RR selectivity is switched to the C 2 pathway, with a substantially promoted [Formula: see text] of 79% and a high partial current density of -421 mA cm -2 . Our discovery of tuning intermediate coverages suggests a powerful catalyst design strategy for different CO 2 electroreduction pathways., Competing Interests: Conflict of interest The authors declare that they have no conflict of interest., (Copyright © 2022 Science China Press. Published by Elsevier B.V. All rights reserved.)

Palladium (Pd) is supposed to be one of the most promising catalytic metals towards ethanol (C 2 H 5 OH) oxidation reaction (EOR). However, Pd electrocatalysts easily suffer from the poisoning of the intermediates (especially CO), resulting in the quick decay of EOR catalysis. Herein, inspired by the Brønsted-Lowry acid-base theory, a "attraction-repulsion" concept is proposed to guide the surface structure engineering toward EOR catalysts. Specifically, we induce Bi(OH) 3 species as Brønsted base onto PdBi nanoplates to effectively repel the adsorption of CO intermediates. The PdBi-Bi(OH) 3 nanoplates show an impressive mass activity of 4.46 A mg Pd -1 during the EOR catalysis and keep excellent stability. Both the stability and enhanced performance are attributed by the interfacial Brønsted base Bi(OH) 3 which can selectively attract and repel reactants and intermediates, as evidenced from in situ measurements and theoretical views., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Inc. All rights reserved.)

The fermentation of biomass allows for the generation of major renewable ethanol biofuel that has high energy density favorable for direct alcohol fuel cells in alkaline media. However, selective conversion of ethanol to either CO 2 or acetate remains a great challenge. Especially, the ethanol-to-acetate route usually demonstrates decentoxidation current density relative to the ethanol-to-CO 2 route that contains strongly adsorbed poisons. This makes the total oxidation of ethanol to CO 2 unnecessary. Here, we present a highly active ethanol oxidation electrocatalyst that was prepared by in situ decorating highly dispersed Mo sites on Pd nanosheets (MoO x /Pd) via a surfactant-free and facile route. We found that ∼2 atom % of Mo on Pd nanosheets increases the current density to 3.8 A mg Pd -1 , around 2 times more active relative to the undecorated Pd nanosheets, achieving nearly 100% faradic efficiency for the ethanol-to-acetate conversion in an alkaline electrolyte without the generation of detectable CO 2 , evidenced by in situ electrochemical infrared spectroscopy, nuclear magnetic resonance, and ion chromatography. The selective and CO 2 -free conversion offers a promising strategy through alcohol fuel cells for contributing comparable current density to power electrical equipment while for selective oxidation of biofuels to useful acetate intermediate for the chemical industry.

A methanol economy will be favored by the availability of low-cost catalysts able to selectively oxidize methanol to formate. This selective oxidation would allow extraction of the largest part of the fuel energy while concurrently producing a chemical with even higher commercial value than the fuel itself. Herein, we present a highly active methanol electrooxidation catalyst based on abundant elements and with an optimized structure to simultaneously maximize interaction with the electrolyte and mobility of charge carriers. In situ infrared spectroscopy combined with nuclear magnetic resonance spectroscopy showed that branched nickel carbide particles are the first catalyst determined to have nearly 100 % electrochemical conversion of methanol to formate without generating detectable CO 2 as a byproduct. Electrochemical kinetics analysis revealed the optimized reaction conditions and the electrode delivered excellent activities. This work provides a straightforward and cost-efficient way for the conversion of organic small molecules and the first direct evidence of a selective formate reaction pathway., (© 2020 Wiley-VCH GmbH.)