Three-dimensional porous nanoarchitecture constructed by ultrathin NiCoBOx nanosheets as a highly efficient and durable electrocatalyst for oxygen evolution reaction

It is still challenging to develop highly efficient catalysts for oxygen evolution reaction due to their sluggish kinetics for water splitting. To address such issue, herein, for the first time, self-assembled three-dimensional porous nanoarchitecture, constructed by ultrathin cobalt-nickel-boron oxide (NiCoBOx) nanosheets, is synthesized by a facile borohydride/amine hydrolysis strategy. As an oxygen evolution electrocatalyst, the NiCoBOx nanoarchitecture delivers excellent performance with a very low overpotential of 290 mV to achieve 10 mA cm(-2) and a small Tafel slope of 59.2 mV dec(-1) in an alkaline medium, which is analogous to the performance of RuO2. Moreover, it shows outstanding physiochemical long-term stability with excellent current density retention even after 70 h. Its OER performance is reassessed to the benchmark catalyst and practically very virtuous within most reported Ni/Co-based OER electrocatalysts. The rationally designed 3D porous nanoarchitecture of borate anchored ultrathin NiCoOx nanosheets (NiCoB)-O-x favours the transportation of electrons and diffusion of ions during catalysis process, thus significantly enhancing its catalytic activity. This work provides a facile and low-cost synthesis strategy to fabricate 3D porous electrocatalyst with rational nanoarchitecture for highly efficient and stable OER. (C) 2019 Elsevier Ltd. All rights reserved.