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Organic electrode materials are promising for next‐generation energy storage materials due to their environmental friendliness and sustainable renewability. However, problems such as their high solubility in electrolytes and low intrinsic conductivity have always plagued their further application. Polymerization to form conjugated organic polymers can not only inhibit the dissolution of organic electrodes in the electrolyte, but also enhance the intrinsic conductivity of organic molecules. Herein, we synthesized a new conjugated organic polymer (COPs) COP500‐CuT2TP (poly [5,10,15,20‐tetra(2,2′‐bithiophen‐5‐yl) porphyrinato] copper (II)) by electrochemical polymerization method. Due to the self‐exfoliation behavior, the porphyrin cathode exhibited a reversible discharge capacity of 420 mAh g−1, and a high specific energy of 900 Wh Kg−1 with a first coulombic efficiency of 96 % at 100 mA g−1. Excellent cycling stability up to 8000 cycles without capacity loss was achieved even at a high current density of 5 A g−1. This highly conjugated structure promotes COP500‐CuT2TP combined high energy density, high power density, and good cycling stability, which would open new opportunity for the designable and versatile organic electrodes for electrochemical energy storage. [ABSTRACT FROM AUTHOR]

Owing to outstanding performances, nickel‐based electrocatalysts are commonly used in electrochemical alcohol oxidation reactions (AORs), and the active phase is usually vacancy‐rich nickel oxide/hydroxide (NiOxHy) species. However, researchers are not aware of the catalytic role of atom vacancy in AORs. Here, we study vacancy‐induced catalytic mechanisms for AORs on NiOxHy species. As to AORs on oxygen‐vacancy‐poor β‐Ni(OH)2, the only redox mediator is electrooxidation‐induced electrophilic lattice oxygen species, which can only catalyze the dehydrogenation process (e.g. the electrooxidation of primary alcohol to carboxylic acid) instead of the C−C bond cleavage. Hence, vicinal diol electrooxidation reaction involving the C−C bond cleavage is not feasible with oxygen‐vacancy‐poor β‐Ni(OH)2. Only through oxygen vacancy‐induced adsorbed oxygen‐mediated mechanism, can oxygen‐vacancy‐rich NiOxHy species catalyze the electrooxidation of vicinal diol to carboxylic acid and formic acid accompanied with the C−C bond cleavage. Crucially, we examine how vacancies and vacancy‐induced catalytic mechanisms work during AORs on NiOxHy species. [ABSTRACT FROM AUTHOR]

Nickel hydroxide (Ni(OH)2) is a promising electrocatalyst for the 5‐hydroxymethylfurfural oxidation reaction (HMFOR) and the dehydronated intermediates Ni(OH)O species are proved to be active sites for HMFOR. In this study, Ni(OH)2 is modified by platinum to adjust the electronic structure and the current density of HMFOR improves 8.2 times at the Pt/Ni(OH)2 electrode compared with that on Ni(OH)2 electrode. Operando methods reveal that the introduction of Pt optimized the redox property of Ni(OH)2 and accelerate the formation of Ni(OH)O during the catalytic process. Theoretical studies demonstrate that the enhanced Ni(OH)O formation kinetics originates from the reduced dehydrogenation energy of Ni(OH)2. The product analysis and transition state simulation prove that the Pt also reduces adsorption energy of HMF with optimized adsorption behavior as Pt can act as the adsorption site of HMF. Overall, this work here provides a strategy to design an efficient and universal nickel‐based catalyst for HMF electro‐oxidation, which can also be extended to other Ni‐based catalysts such as Ni(HCO3)2 and NiO. [ABSTRACT FROM AUTHOR]