Chlorophyll‐Based Organic Heterojunction on Ti₃C₂T_<i>x</i> MXene Nanosheets for Efficient Hydrogen Production

Abstract

Abstract The Z‐scheme process is a photoinduced electron‐transfer pathway in natural oxygenic photosynthesis involving electron transport from photosystem II (PSII) to photosystem I (PSI). Inspired by the interesting Z‐scheme process, herein a photocatalytic hydrogen evolution reaction (HER) employing chlorophyll (Chl) derivatives, Chl‐1 and Chl‐2, on the surface of Ti 3 C 2 T x MXene with two‐dimensional accordion‐like morphology, forming Chl‐1@Chl‐2@Ti 3 C 2 T x composite, is demonstrated. Due to the frontier molecular orbital energy alignments of Chl‐1 and Chl‐2, sublayer Chl‐1 is a simulation of PSI, whereas upper layer Chl‐2 is equivalent to PSII, and the resultant electron transport can take place from Chl‐2 to Chl‐1. Under the illumination of visible light (&gt;420 nm), the HER performance of Chl‐1@Chl‐2@Ti 3 C 2 T x photocatalyst was found to be as high as 143 μmol h −1 g cat −1 , which was substantially higher than that of photocatalysts of either Chl‐1@Ti 3 C 2 T x (20 μmol h −1 g −1 ) or Chl‐2@Ti 3 C 2 T x (15 μmol h −1 g −1 ).