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The electrosynthesis of valuable chemical feedstocks and fuels through the CO2 reduction reaction (CO2RR) provides a promising approach to solve the global warming problem and the energy crisis. Numerous studies have been devoted to developing electrocatalysts; however, few studies focus on Pb actives sites as well as the defect engineering of active sites. Herein, an O vacancy-rich PbCO3 electrocatalyst (O-PbCO3) derived Pb2(OH)2(CH3COO)2 precatalyst is reported. X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR) results prove the existence of O vacancies while the X-ray absorption fine structure (XAFS) results reveal the distorted structure of the O-PbCO3. Electrochemical measurements of the O-PbCO3 sample exhibit a remarkable selectivity and activity towards formate of over 90% in a wide range of current densities of 50 to 400 mA cm−2. Further in situ surface-enhanced infrared absorption spectroscopy (SEIRAS) characterization indicates that the O vacancies can optimize the adsorption of the *HCOO intermediate for enhanced CO2RR performance. [ABSTRACT FROM AUTHOR]

Electrocatalytic carbon dioxide/carbon monoxide reduction reaction (CO(2)RR) has emerged as a prospective and appealing strategy to realize carbon neutrality for manufacturing sustainable chemical products. Developing highly active electrocatalysts and stable devices has been demonstrated as effective approach to enhance the conversion efficiency of CO(2)RR. In order to rationally design electrocatalysts and devices, a comprehensive understanding of the intrinsic structure evolution within catalysts and micro‐environment change around electrode interface, particularly under operation conditions, is indispensable. Synchrotron radiation has been recognized as a versatile characterization platform, garnering widespread attention owing to its high brightness, elevated flux, excellent directivity, strong polarization and exceptional stability. This review systematically introduces the applications of synchrotron radiation technologies classified by radiation sources with varying wavelengths in CO(2)RR. By virtue of in situ/operando synchrotron radiationanalytical techniques, we also summarize relevant dynamic evolution processes from electronic structure, atomic configuration, molecular adsorption, crystal lattice and devices, spanning scales from the angstrom to the micrometer. The merits and limitations of diverse synchrotron characterization techniques are summarized, and their applicable scenarios in CO(2)RR are further presented. On the basis of the state‐of‐the‐art fourth‐generation synchrotron facilities, a perspective for further deeper understanding of the CO(2)RR process using synchrotron radiation analytical techniques is proposed. [ABSTRACT FROM AUTHOR]

Electrochemical CO2 reduction reaction (CO2RR) provides a promising way for producing value‐added fuels and chemicals via renewable electricity. However, the dynamic reconstruction of electrocatalysts of atomic active sites hinders in‐depth understanding of catalytic mechanism and further industrial application, especially under ampere‐level current density conditions. In this work, electro‐induced crystallization is reported over an amorphous Indium hydroxide gel (In gel) catalyst, which generates active sites for efficient and selective CO2RR. Molecular dynamic calculation reveals the crystallization process can maintain amorphous In‐OH species on the surface while generating crystallized metallic In under electroreduction condition; structural characterizations prove that the derived partially crystallized In gel is stable consisting of amorphous/crystalline interface, even biased at a high polarization potential of −4 V versus reversible hydrogen electrode. The resultant partially crystalized In gel exhibits a highly selective CO2RR performance toward formate under an ampere‐level current density up to 1200 mA cm−2 simultaneously with 91.89% Faradaic efficiency, which can motivate a high formate generation rate of 20.55 mmol h−1 cm−2. The operando Raman spectroscopic and density functional theoretic results demonstrate the optimized adsorption of *HCOO intermediate for the enhanced formate activity and selectivity over the partially crystallized In gel. [ABSTRACT FROM AUTHOR]

Polar materials with spontaneous polarization (Ps) have emerged as highly promising photocatalysts for efficient photocatalytic H2 evolution owing to the Ps‐enhanced photogenerated carrier separation. However, traditional inorganic polar materials often suffer from limitations such as wide band gaps and poor carrier transport, which hinders their photocatalytic H2 evolution efficiency. Here, we rationally synthesized a series of isostructural two‐dimensional (2D) aromatic Dion–Jacobson (DJ) perovskites, namely (2‐(2‐Aminoethyl)pyridinium)PbI4 (2‐APDPI), (3‐(2‐Aminoethyl)pyridinium)PbI4 (3‐APDPI), and (4‐(2‐Aminoethyl)pyridinium)PbI4 (4‐APDPI), where 2‐APDPI and 4‐APDPI crystalize in polar space groups with piezoelectric constants (d33) of approximately 40 pm V−1 and 3‐APDPI adopts a centrosymmetric structure. Strikingly, owing to the Ps‐facilitated separation of photogenerated carriers, polar 2‐APDPI and 4‐APDPI exhibit a 3.9‐ and 2.8‐fold increase, respectively, in photocatalytic H2 evolution compared to the centrosymmetric 3‐APDPI. As a pioneering study, this work provides an efficient approach for exploring new polar photocatalysts and highlights their potential in promoting photocatalytic H2 evolution. [ABSTRACT FROM AUTHOR]

Electrocatalytic water splitting is one of the most commercially valuable pathways of hydrogen production especially combined with renewable electricity; however, efficient and durable electrocatalysts are urgently needed to reduce electric energy consumption. Here, we reported a Ru and Fe co‐doped Mo2C on nitrogen doped carbon via a controllable two‐step method, which can be used for efficient and enduring hydrogen evolution reaction. At 10, 100 and 200 mA cm−2 in acidic electrolyte, the resultant Ru‐Fe/Mo2C@NC delivered low overpotentials of 31, 78 and 103 mV, respectively, which are comparable to that of the commercial Pt/C (20 wt %). At an applied current density of 100 mA cm−2, stable hydrogen production was conducted for 120 h without obvious degradation. In alkaline media, Ru‐Fe/Mo2C@NC can also deliver a current density of 100 mA cm−2 for more than 100 h. Furthermore, the Ru‐Fe/Mo2C@NC electrocatalyst was used as cathode in an anion exchange membrane water electrolyzer under industrial environments for robust hydrogen production. The characterization and electrochemical results prove the synergism effects between Ru, Fe dopants and Mo2C for promoting hydrogen evolution activity. This work would pave a new avenue to fabricate low‐cost, high‐performance hydrogen evolution electrocatalysts for industrial water electrolyzers. [ABSTRACT FROM AUTHOR]

Designing highly excellent and stable catalysts for alkaline oxygen evolution reaction (OER) is gradually pivotal for clean energy development. In this work, a heterogeneous Fe‐doped Ni(OH)2 (Ni/Fe‐0.1) was developed via simple one‐step electrodeposition onto nickel mesh. The heterogeneous interface structure generates sufficient active sites, significantly improving OER performance with an overpotential of 174 mV at 10 mA cm−2 (η10), while Tafel slope is only 43.0 mV dec−1. In particular, Ni/Fe‐0.1 is still able to operate stably at a current density of 1 A cm−2 for 100 h without obvious potential decay. The oxidation of Ni2+ to Ni3+ was detected by X‐ray photoelectron spectroscopy, proving that the heterogeneous catalyst could stabilize the high‐valence state of nickel as active sites to its superior OER performance. This work provides a convenient synthetic strategy for forming heterogeneous catalysts toward efficient water electrolysis. [ABSTRACT FROM AUTHOR]

Electroreduction of CO2 to valuable multicarbon (C2+) products is a highly attractive way to utilize and divert emitted CO2. However, a major fraction of C2+ selectivity is confined to less than 90% by the difficulty of coupling C-C bonds efficiently. Herein, we identify the stable Cu0/Cu2+ interfaces derived from copper phosphate-based (CuPO) electrocatalysts, which can facilitate C2+ production with a low-energy pathway of OC-CHO coupling verified by in situ spectra studies and theoretical calculations. The CuPO precatalyst shows a high Faradaic efficiency (FE) of 69.7% towards C2H4 in an H-cell, and exhibits a significant FEC2+ of 90.9% under industrially relevant current density (j = −350 mA cm−2) in a flow cell configuration. The stable Cu0/Cu2+ interface breaks new ground for the structural design of electrocatalysts and the construction of synergistic active sites to improve the activity and selectivity of valuable C2+ products. The electrosynthesis of multicarbon products from CO2 is a highly attractive way to utilize emitted CO2. Here, the authors report in situ formed Cu0/Cu2+ interfaces from copper phosphate-based electrocatalysts for promoting selectivity toward multicarbon products through OC-CHO coupling. [ABSTRACT FROM AUTHOR]

In this study, ruthenium-doped CoFe-based layered double hydroxides on Ni foam (CoFe-ZLDH/Ru@NF) were fabricated via an etching-precipitation strategy. The resultant CoFe-ZLDH/Ru@NF exhibited excellent activity, showing low overpotentials of 219.8 mV and 60.9 mV to reach the current density of 10 mA cm−2 for the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), respectively. As a bifunctional electrocatalyst, it was assembled in an anion exchange membrane water electrolyser (AEMWE) unit, performing as an anode and cathode simultaneously, which only required a cell voltage of 2.33 V to accomplish the industrial level current density of 1 A cm−2 and operated steadily for over 12 h, making it promising for utilization in hydrogen production. [ABSTRACT FROM AUTHOR]