Cobalt single atoms coordinated with planar four nitrogen atoms (Co 1 N 4 ) represent an efficient electrocatalyst for oxygen evolution reaction (OER), whereas the large energy barrier of Co-O-H dehydrogenation limits the OER activity. Herein, axial phosphate (PO 4 ) coordination is incorporated in Co 1 N 4 single atoms of cobalt phthalocyanine@carbon nanotubes (P-CoPc@CNT), so as to boost the intrinsic OER performance through manipulating the reaction pathway. With a relative low mass loading of Co (2.7%), the P-CoPc@CNT shows remarkable alkaline OER activity with the overpotential of 300 mV and Tafel slope of 41.7 mV dec −1 , which dramatically outperforms the CoPc@CNT without axial PO 4 coordination. Based on mechanistic analysis, the axial PO 4 coordination directly participates in the OER cycle by the transformation of axial ligand. Specially, the Co-O-H dehydrogenation process is replaced by the dehydrogenation of HPO 4 -Co 1 N 4 intermediate, which largely decreases the energy barrier and thus benefits the whole OER process.

1987, Corrigan discovered a trace amount of Fe doped nickel oxide electrode can significantly enhance the OER. [3] Since then, most of the unmodified NiFe (oxy) hydroxide has been gradually pushed to the forefront, yet its catalytic activity (today above overpotentials of 0.3 V at 100 mA cm −2 ) is still insufficient compared to the thresholds of economic viability predicted by techno-economic assessments. [4] Tuning the oxygenated intermediates adsorption of the OER process by manipulating the electronic structure of the active site is crucial to further improve catalytic performance, which would render NiFe-based industrial water splitting electrolyzers more competitive. [5] Vacancy engineering, especially for metal cation vacancies with multifarious electron configuration and orbit has been implemented for enhancing OER activities via manipulating the energy band structure, carrier concentration, and spin state. [6] Beyond that, recent reports indicate that atomic cation-vacancy can improve the lattice bond energy in NiFe (oxy) hydroxide and thus inhibit Fe ion leaching to enhance the stability during OER. [7] However, as vacancies are introduced and concentrations increase, the catalyst structure will tend to be destroyed and its electrical conductivity will Nickel-iron oxygen evolution catalysts have been under the spotlight as substitutes for precious metals, however, they rarely operate efficiently in practical industrial electrolyzers due to their moderate activity. Guided by density functional theory, the interaction of cation vacancies and dopants can manipulate d band centers, thus gaining near-optimal binding energies of the oxygenated intermediates and ultralow potentials. This principle is implemented experimentally by catalysis operando variations synthesis, more specifically, in situ Mo leaching from high-entropy Co, Mo co-doped NiFe hydroxide precursors form Co dopant and cation vacancy coexistent NiFe oxyhydroxide. Operando electrochemical spectroscopy uncovers that dual-cation-defects promote the readier oxidation transition of metal sites, thus contributing to a low overpotential of 255 mV at 100 mA cm −2 . Furthermore, dual-regulated NiFe oxyhydroxide electrodes operate stably at 8 A in practical industrial electrolyzers with ultralow energy consumption of ≈4.6 kWh m −3 H 2 , verifying the feasibility of lab-constructed novel catalysts towards industrialization.

Water Splitting In article number 2203595, Youwen Liu, Yan Liu, Jiakun Fang, Lin Yu and co‐workers fabricate a Co dopant and cation vacancy coexistent NiFe oxyhydroxide by in situ Mo leaching from high‐entropy Co, Mo co‐doped NiFe hydroxide precursors. Dual‐regulated NiFe oxyhydroxide electrodes operate stably at 8 A in practical industrial electrolyzers with ultralow energy consumption of 4.6 kWh m−3 H2, verifying the feasibility of lab‐constructed novel catalysts for industrialization.