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Electrocatalytic reduction of CO2 to formate is believed to be one of the most promising technologies for producing clean fuels and valuable chemicals and for tackling the global warming problem. Herein, a novel synthesis strategy is presented for Bi‐based catalyst in CO2 reduction reaction (CO2RR). With the addition of acetic acid into the mother solution, heterostructured Bi/Bi2O3 nanoplates with abundant O vacancies (Bi/Bi2O3–Ov) and tailored coordination environments of the Bi ions are successfully synthesized, which exhibit excellent catalytic activity for CO2RR and high selectivity for formate generation with wide operable windows of pH (neutral to alkaline) and potential. In particular, the faradic efficiency (HCOOH) reaches ≥90% in a wide potential range of −0.7–−1.35 V versus reversible hydrogen electrode in neutral media, which dwarf most of the state‐of‐the‐art Bi‐based catalysts for CO2RR reported to date. Combined experimental and theoretical results show that the abundant O vacancies create frustrated Lewis pairs at the heterointerfaces with favorable adsorption characteristics, thereby facilitating the CO2RR process. This work opens up a new approach to promoting the catalytic activity and selectivity of Bi‐based materials for CO2RR by combining coordination and heterointerface engineering. [ABSTRACT FROM AUTHOR]

Efficient noble‐metal free electrocatalyst for oxygen evolution reaction (OER) is critical for large‐scale hydrogen production via water splitting. Inspired by Nature's oxygen evolution cluster in photosystem II and the highly efficient artificial OER catalyst of NiFe layered double hydroxide (LDH), we designed an electrostatic 2D‐2D assembly route and successfully synthesized a 2D LDH(+)‐Birnessite(−) hybrid. The as‐constructed LDH(+)‐Birnessite(−) hybrid catalyst showed advanced catalytic activity and excellent stability towards OER under a close to industrial hydrogen production condition (85 °C and 6 M KOH) for more than 20 h at the current densities larger than 100 mA cm−2. Experimentally, we found that besides the enlarged interlayer distance, the flexible interlayer NiFe LDH(+) also modulates the electronic structure of layered MnO2, and creates an electric field between NiFe LDH(+) and Birnessite(−), wherein OER occurs with a greatly decreased overpotential. DFT calculations confirmed the interlayer LDH modulations of the OER process, attributable to the distinct electronic distributions and environments. Upshifting the Fe‐3d orbitals in LDH promotes electron transfer from the layered MnO2 to LDH, significantly boosting up the OER performance. This work opens a new way to fabricate highly efficient OER catalyst for industrial water oxidation. [ABSTRACT FROM AUTHOR]

Ceria‐based catalysts for the oxygen evolution reaction (OER) have received keen interest in recent years owing to their potential excellent cost performance. However, despite a flurry of research activities, the mechanism on how ceria activates those hybrid catalysts is still puzzling. Herein, by controllably modifying the oxidation state of Ce in ceria, it was revealed that creating Ce3+ species, which are redox‐coupled to Ce4+ under OER conditions, could enhance the conductivity and optimize the OH* binding, leading to greatly improved OER activity of the catalysts. More importantly, the ceria‐based hybrid catalysts also exhibited excellent long‐term stability even when operating at a high current density of 50 mA cm−2 in the strong alkaline electrolyte of 6 m KOH for more than 50 h. This work unveils the underlying role of ceria in improving the activity/stability of ceria‐based catalysts and opens the way to design and fabricate ceria‐based electrocatalysts for water splitting. [ABSTRACT FROM AUTHOR]