Selective N2/H2O adsorption onto 2D amphiphilic amorphous photocatalysts for ambient gas-phase nitrogen fixation

Abstract

The gas-phase Haber–Bosch process has been the main industrial source of ammonia over the last century. However, its reliance on high temperature and high pressure for enormous energy input emits greenhouse gas to air and is associated with the depletion of fossil fuels. The need of the hour is to replace this method with environmentally sustainable processes, among which, photocatalytic nitrogen reduction has attracted much attention. In this work, we report a low cost, scalable manufacturing of gas-phase photoreactors for nitrogen reduction under ambient conditions based on 2D amorphous molybdenum oxysulfides, i.e. MoS2+x-MoO3-y composites. They show excellent nitrogen reduction efficiencies of ~141 μmol/g/h with remarkably stable performance. The amphiphilic MoS2+x and MoO3-y composites selectively chemisorb and activate N2 and H2O molecules, respectively, and enable multiple photodriven redox reactions towards NH3 evolution. Such photo-reactors for ambient ammonia synthesis provides a potentially feasible route towards next-generation gas-phase industrial ammonia production.