Coupling boron-modulated bimetallic oxyhydroxide with photosensitive polymer enable highly-active and ultra-stable seawater splitting

Abstract

Seawater photoelectrolysis is showing huge potential in green energy conversion field, yet it is still a formidable challenge to develop one catalyst that can drive the electrolysis reaction stably, economically and efficiently. Motivated by this point, the inorganic–organic hybridization strategy is proposed to in-situ construct one hierarchical electrode via concurrent electroless plating and polymerization, which assures the growth of boron-modulated nickel–cobalt oxyhydroxide nanoballs and photosensitive polyaniline nanochains on the self-supporting Ti-based foil (B-CoNiOOH/PANI@TiO2/Ti). Upon inducing photoelectric effect (PEE), the designed target electrode delivers overpotentials as low as 196 and 398 mV at 100 mA cm−2 for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively, corresponding to an activity enhancement by about 15% as compared to those without PEE. Inspiringly, when served as bifunctional electrocatalysts for overall seawater electrolysis, it can stably maintain at 200 mA cm−2 with negligible decay over 72 h. Further analysis reveals that the exceptional catalytic performance can be credit to the B-CoNiOOH, polyaniline (PANI) and TiO2 subunit coupling-induced physically and chemically synergistic catalysis effect such as admirable composition stability, photoelectric function and adhesion capability. The finding in this contribution may trigger much more broad interest to the novel hybrid catalysts consisting of photosensitive polymer and transition metal-based electrocatalysts.