g-C3N4/Ti3C2Tx (MXenes) composite with oxidized surface groups for efficient photocatalytic hydrogen evolution

Abstract

Ti₃C₂T_x is a 2-dimensional titanium carbide material featuring outstanding electrochemical properties. In spite of this, application of Ti₃C₂T_x as co-catalyst in photo-catalysis is rarely explored, probably because of its metallic nature and hydrophilic surface. Given that Ti₃C₂T_x with different surface terminations exhibits large differences in catalytic, electrochemical and chemical properties, we demonstrate an improvement of the photocatalytic activity of Ti₃C₂T_x as a co-catalyst by annealing a composite of carbon nitride and Ti₃C₂T_x. Ti₃C₂T_x with an oxygen terminated surface improved the separation of electron–hole pairs and resulted in a 105% enhancement in the production ratio of hydrogen evolution compared to control samples. The best hydrogen production performance reached as high as 88 μmol h⁻¹ g_cat⁻¹. The apparent quantum yield (AQY) reached as high as 1.27%. The DFT calculations also demonstrate a better hydrogen evolution on Ti₃C₂ with oxygen surface termination.