Building Mo2C/C/TCN heterojunction for efficient noble-metal-free plastic photoreforming and hydrogen generation

Abstract

Photocatalytic water splitting converts sunlight directly to storable H₂, but commonly involves the use of a hole sacrificial agent and a noble metal cocatalyst, leading to the waste of energy and increasing cost. Herein, we report a Mo₂C/C/TCN heterojunction for overcoming these shortages through a combination system to realize H₂ generation and plastic reforming at the same time. Mo₂C/C/TCN, consisting of thiophene-embedded polymeric carbon nitride (TCN) and molybdenum carbide anchored on graphite nanosheet (Mo₂C/C), was prepared via electrostatic self-assembly. In the heterojunction, TCN performed as an electron donor, Mo₂C acted as an electron acceptor and H₂ evolution active center, while the graphite (C) in Mo₂C/C served as an electron transport medium. Owing to its hetero-structure, the visible light utilization efficiency as well as photoinduced charge separation and migration efficiency of the catalyst Mo₂C/C/TCN were greatly strengthened compared to the pristine polymeric carbon nitride (CN). As a result, Mo₂C/C/TCN exhibited satisfactory visible-light-driven waste plastic photoreforming and high H₂ generation activity. The optimized photocatalytic H₂ evolution rate over Mo₂C/C/TCN reached 188.7 μmol h⁻¹, which was 7.1 times of that over Pt/CN in 10 vol% triethanolamine (TEOA), far ahead of the research that has been reported. Additionally, Mo₂C/C/TCN exhibited adorable photoreforming efficiency of polylactic acid (PLA) and bisphenol A (BPA) under visible light. This work provides an efficient approach for lowering cost, enhancing optical absorption, and inhibiting charge recombination for higher photocatalytic performance and wilder applications.