In situ modification of cobalt on MXene/TiO₂ as composite photocatalyst for efficient nitrogen fixation

Modulation of the binding of the reactant or product species with catalysts is an effective approach to optimize the photocatalytic activity. Herein, we explored the relationship between the binding of reactant (N₂) and product (NH₃) with catalyst and the photocatalytic nitrogen fixation activity. The surface reactivity of nitrogen with water was tuned by introducing Co into the MXene@TiO₂ catalysts, which the TiO₂ nanoparticle derived from the in-situ growth on the surface of MXene nanosheets. Co modified adjusted the chemisorption equilibrium of the catalyst for reactant (N₂) and product (NH₃), thus promoted product desorption and efficiency of the active site. Remarkably, the optimal catalyst (MXene/TiO₂/Co-0.5%) exhibited outstanding NH₄⁺ production rate (110 μmol g^-1 h^-1) and excellent stability in pure water without any hole sacrificial agent under Ultraviolet-Visible (UV-vis) light in N₂ and air ambient.