Boosting photocatalytic performance of CdxZn1–xS for H2 production by Mo2C MXene with large interlayer distance

Abstract

Here we report a novel heterostructure with ultrahigh photocatalytic performance for H₂ production. The heterostructure consists of Cd_xZn_1−xS solid solution and two dimensional Mo₂C MXene. The Mo₂C MXene works as a co-catalyst, which was made from Mo₂Ga₂C by etching in cetyltrimethylammonium bromide (CTAB) solution at 160 °C for 24 h. Different from the MXene made by the general method of fluoric acid etching, the Mo₂C MXene made by this method had ultra large interlayer space (lattice parameter c = 24.5 Å) due to the in situ intercalation of CTA⁺. Thereafter, the Mo₂C MXene without a delamination process was used as the substrate to grow Cd_0.8Zn_0.2S (CZS) at room temperature, followed by heating in a hydrothermal process to achieve the phase conversion of CZS from sphalerite to wurtzite. The CZS/Mo₂C photocatalyst (mass ratio of Mo₂C : CZS = 0.2 : 1) achieves an ultrahigh photocatalytic H₂ production activity of 44.19 mmol g⁻¹ h⁻¹, surpassing pure CZS by a satisfying factor of ≈2289%. It is higher than that of other MXene-co-catalysts and other noble-metal-free CSZ-based photocatalysts reported to date.