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The electrochemical CO2 reduction reaction (CO2RR) to CO is closely correlated with appropriate sorption of *COOH and *CO species toward the electrode surface, and the proton transfer process that often competes with the hydrogen evolution reaction (HER). Herein, an unconventional p–d orbital hybridization induced by doping of S to the second coordination layer of atomically dispersed pyrrole-type Fe–N4 (S/Fe–poN4–C) could not only modulate the binding strength between *COOH and pyrrole-type Fe single atoms but also facilitate the succedent desorption of *CO, effectively hindering the occurrence of the HER. An excellent CO2RR performance was achieved in an H-type cell over S/Fe–poN4–C, with CO Faraday efficiency of 98.2% and turnover frequency of 4621.2 h−1, superior to the S-free pyridine-type Fe–N4 catalyst and previously reported electrodes. In situ characterization techniques and theoretical calculations demonstrated that the constructed p–d orbital hybridization suitably balanced the adsorption of the *COOH intermediate by accelerating proton transfer and further desorption of *CO by optimizing the nitrogen coordination environment of the electrocatalyst, which could also stabilize the atomic Fe sites to avoid aggregation. The remote p–d orbital hybridization strategy offers an alternative approach for more precious regulation of both the electronic and coordination structure of the electrodes for highly selective CO2RR. [ABSTRACT FROM AUTHOR]

The slow kinetic process of the oxygen evolution reaction (OER) and poor electrochemical stability in acidic environments of electrocatalysts seriously restrict the efficiency of hydrogen production from proton exchange membrane water electrolyzers (PEMWEs). In recent years, developing corrosion-resistant and redox-active doped TiO2 with heterogeneous atoms has become an effective strategy to address this challenge. However, most of the reported studies only explore single-element doped TiO2-supported catalysts, and there are few reports comparing the doping effects of various elements at the experimental level, which is crucial for screening high-performance OER electrocatalysts. In this work, seven different metal elements M (M = V, Mn, Fe, Ni, Cu, Nb, W) are selected for doping anatase TiO2 with the same molar ratio (M/Ti) and combined with IrO2 nanoparticles to form M-doped TiO2-supported IrO2 (M–TiO2@IrO2) electrocatalysts. Electrochemical OER activity and stability results indicate that W–TiO2@IrO2 exhibits the best performance among all these catalysts in terms of comprehensively regulating the conductivity of TiO2 and the activity and stability of IrOx within the range of experimental design in this work, which originates from the appropriate energy band structure obtained through W doping, optimizing the intrinsic conductivity of the support and interfacial electronic structure between the metal oxide and support. [ABSTRACT FROM AUTHOR]