Controlled interfacial charge transfer and photon–electron conversion of Ag/Cu-supported MXene heterostructures for applications as PEC anode materials

Abstract

The construction of two-dimensional materials and noble metal heterostructures offers enhanced, controllable charge transfer and photovoltaic conversion efficiency, and they have been widely applied in fields such as photoelectrochemical energy conversion (PEC). Herein, we provide a comprehensive summary of recent advances in noble metal and MXene materials and their heterostructures. We then introduce and discuss various structural design strategies, along with the regulation and structure–activity relationship of Ag/Cu-supported MXene heterostructures prepared via two-step hydrothermal and magnetron sputtering. The combination of Ag/Cu with Ti₃C₂O₂ to form an ohmic contact enhances the efficiency of the electron–hole separation and solves the surface stacking problem caused by the layered structure of MXene. Density functional theory (DFT) calculations were performed to reveal the density of states for “cluster-interface”, “particle-interface” and “nanocoating-interface” configurations of Ag/Cu and MXene with different alignment sites, highlighting their mechanisms for regulating the electronic band structure of MXene. Additionally, DFT determined the band and charge population of MXene@M heterostructures based on different alignment sites and interphase. PEC and transient absorption experiments confirm that Ag/Cu-supported MXene heterojunctions promote photo-induced charge separation and enhance interfacial charge transport efficiency. This study provides a novel strategy for the design and synthesis of noble metals and MXene materials and provides valuable guidance for achieving high-efficiency PEC, which will greatly enrich their applications in photonic and energy-related environmental devices.