Photo-thermal synergic enhancement of CoxFeAl-LDHs for hydrogen generation from hydrolysis of NaBH4

The production of hydrogen from sodium borohydride (NaBH 4 ) with a suitable catalyst is a promising route for the hydrogen industry. The exploration of the energy-saving catalysts with visible light response and photothermal effect is necessary for utilizing solar energy in hydrogen utilization from hydrolysis of NaBH 4 . In this study, a series of photo-thermal catalysts of Co x FeAl layered double hydroxides (Co x FeAl-LDHs x  = 4, 6, 8) with abundant oxygen vacancy (V o ) are successfully synthesized for photo-thermal synergic catalytic H 2 generation from hydrolysis of NaBH 4 . Co x FeAl-LDHs differ in bandgap, V o concentration, and photo-thermal performance, with Co 6 FeAl-LDH show the highest concentration of V o and most efficient photo-thermal performance under 400–700 nm irradiation. Co 6 FeAl-LDH can significantly lower the activation energy of the hydrolysis of NaBH 4 ( E a  = 35.46 kJ mol −1 ) and demonstrates excellent photo-thermal synergic performance with H 2 generation rate of 3.38 mol g −1 h −1 without additional heat source. The mechanism study shows that the h + , ∙OH, and V o in Co x FeAl-LDHs also play essential roles in the hydrolysis of NaBH 4 . This work develops a hydrotalcite-based photo-thermal synergistic catalyst, which provides a new approach for the design of sodium borohydride hydrolysis catalysts for hydrogen production.