Activation of urchin-like Ni-doped W18O49/NF by electrochemical tuning for efficient water splitting

The electrochemical conversion is closely correlated with the electrocatalytic activities of the electrocatalyst. Herein, the urchin-like Ni-doped W18O49/NF with enriched active sites was prepared by solvothermal method followed by a low-temperature pyrolysis treatment was reported. Results demonstrate that the incorporation of Ni-doping triggers the lattice distortion of W18O49 for the increasement of oxygen defects. Further, high-valent W6+ are partially reduced to low-valent W4+, wherein the electrons originate from the oxidation process of Ni2+ to Ni3+. The Ni3+ ions show an enhanced orbital overlap with the OER reaction intermediates. The generated W4+ ions contribute to release oxygen vacancies, eventually reorganizing Ni-doped W18O49/NF to unique electrochemical active species with a special amorphous-crystalline interface (AM/NiWOx/NiOOH/NF). Simultaneously, the reconstruction results in an optimized valence band and conduction band. Eventually, the resultant AM/NiWOx/NiOOH/NF with abundant active sites and improved oxidation/reduction capability exhibits more superior catalytic performance compared with the Ni-doped W18O49/NF counterpart. This study gives more insights in the electrochemical evolution of the tungsten-based oxide and provides effective strategies for optimizing the catalytic activity of materials with inherent hydrogen evolution reaction limitations. (C) 2021 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by ELSEVIER B.V. and Science Press. All rights reserved.