Cobalt-Activated Amorphous MoS_x Nanodots Grown In Situ on Natural Attapulgite Nanofibers for Efficient Visible-Light-Driven Dye-Sensitized H₂ Evolution

In situ grown amorphous MoSx catalysts in an organic dye-sensitized system have shown promising performance for catalyzing H2 evolution; however, the inevitable aggregations and low intrinsic activity of the active sites of the thus-obtained MoSx catalysts should be addressed to further enhance their activity. Herein, we report an exceptionally active catalyst of in situ grown Co-activated amorphous MoSx nanodots (<5 nm) on natural attapulgite (ATP) nanofibers (ATP/Co-MoSx) in an Erythrosin B–triethanolamine system employing Co(OH)2-modified ATP [ATP/Co(OH)2] nanofibers as the active support and (NH4)2MoS4 as the precursor of MoSx for photocatalytic H2 evolution under visible-light irradiation (λ ≥ 450 nm). This ATP/Co-MoSx catalyst exhibits a 67.2 times enhancement in H2 evolution activity compared to free MoSx and can achieve an apparent quantum yield as high as 47.7% at 500 nm. Moreover, the ATP/Co-MoSx catalyst shows improved recycling H2 evolution stability over the free MoSx catalyst. It is found that the confinement effects of the active ATP/Co(OH)2 support with high surface area render the in situ grown amorphous Co-MoSx catalyst a reduced size and an improved dispersion while in situ Co doping will lead to the formation of highly active “CoMoS” species, thus synergistically improving the exposure and regulating the electronic properties of the active sites of the ATP/Co-MoSx catalyst to achieve a high activity for H2 evolution. This work presents a facile yet efficient strategy toward designing high-performance MoSx-based hybrid catalysts for solar H2 evolution.