Solar-heating thermocatalytic H2 production from formic acid by a MoS2-graphene-nickel foam composite

Sunlight driven formic acid decomposition has great potential to supply high-purity H2 without consuming fossil fuel-derived energy. However, a trace amount of CO invariably exists in the obtained H2 and the H2 production rate is always lower than 278 mmol g−1 h−1. Here, we found that high quality MoS2 grown on graphene decorated on Ni foam (Ni/G/MoS2) was active and stable for H2 production from thermocatalytic formic acid decomposition without CO presentation and first principles calculation confirmed that the perfect surface terminating sulfur of MoS2 changed the reaction path of intermediates, thus inhibiting the production of CO. Furthermore, a reaction device constructed with Cu2Se can heat catalysts to 120 and 260 °C under 0.25 kW m−2 and 1 kW m−2 (1 Sun) of irradiation, respectively. By using the system of the Cu2Se based reaction device and Ni/G/MoS2, a CO free H2 production rate of 982 mmol g−1 h−1 was achieved under 0.6 Sun of irradiation, 3.5 times higher than the previous record of photocatalytic formic acid decomposition. Therefore, this work provides a new viewpoint for large scale CO free H2 production in a sustainable and green way.