Photocatalyst for High‐Performance H₂ Production: Ga‐Doped Polymeric Carbon Nitride

Abstract

A photocatalyst system is generally comprises a catalyst and cocatalyst to achieve light absorption, electron‐hole separation, and surface reaction. It is a challenge to develop a single photocatalyst having all functions so as to lower the efficiency loss. Herein, the active GaN4 site is integrated into a polymeric carbon nitride (CN) photocatalyst (GCN), which displays an excellent H2 production rate of 9904 μmol h−1 g−1. It is 162 and 3.3 times higher than that of CN with the absence (61 μmol h−1 g−1) and presence (2981 μmol h−1 g−1), respectively, of 1.0 wt % Pt. Under light irradiation the electron is injected and stored at the GaN4 site, where the LUMO locates. The HOMO distributes on the aromatic ring resulting in spatial charge separation. Transient photovoltage discloses the electron‐storage capability of GCN. The negative GaN4 promotes proton adsorption in the excited state. The positive adsorption energy drives H2 desorption from GaN4 after passing the electron to the proton. This work opens up opportunities for exploring a novel catalyst for H2 production.

Accelerating Electron‐Transfer Dynamics by TiO2‐Immobilized Reversible Single‐Atom Copper for Enhanced Artificial Photosynthesis of Urea

“…Cu SA‐TiO 2 exhibited a shorter time of maximum electron extraction (≈0.11 ms) compared with pure TiO 2 (≈3.60 ms), providing direct evidence for the existence of accelerated electron extraction process in Cu SA‐TiO 2 . [ 24 ] Similarly, fluorescence dynamic decay curves of two samples conveyed the same tendency: pure TiO 2 (36.01 ns) versus Cu SA‐TiO 2 (21.82 ns) (Figure 4b and Table S3, Supporting Information), corresponding to the measured results of SPV. [ 25 ] Accordingly, the presence of obvious electron acceleration between Cu species and TiO 2 in Cu SA‐TiO 2 would be responsible for the enhanced performance.…”

Ru/In Dual‐Single Atoms Modulated Charge Separation for Significantly Accelerated Photocatalytic H2 Evolution in Pure Water

“…The photo‐current density of Ru‐In SA/TiO 2 (76.45 µA cm – 2 ) is much higher than those of Ru SA/TiO 2 (55.44 µA cm −2 ), In SA/TiO 2 (30.25 µA cm −2 ), and TiO 2 (19.08 µA cm −2 ) (Figure S14a, Supporting Information). Besides, the electrochemical impedance spectroscopy (EIS) spectra collected in Na 2 SO 4 aqueous solution (0.5 M) show that Ru‐In SA/TiO 2 has the lowest charge transfer resistance compared with Ru SA/TiO 2 , In SA/TiO 2 and TiO 2 (Figure S14b, Supporting Information), [ 28 ] suggesting the dual‐doping of Ru and In single atoms can significantly facilitate the charge transfer. On the other hand, the overpotentials of various catalysts under light irradiation are obviously lower than those of catalysts without light irradiation (Figure S14c, Supporting Information).…”

Efficient Electronic Modulation of g-C 3 N 4 Photocatalyst by Implanting Atomically Dispersed Ag 1 -N 3 for Extremely High Hydrogen Evolution Rates

“…That is to say, the embedded single-atom Ag or Cu into the matrix of g-C 3 N 4 improves the photocatalytic performance of HCNS by adjusting the modulation of electronic structure rather than serving as active sites, which is different from the previously reported results that the introduced single-atom metals acting as active sites. [32][33][34][35][36][37] In addition, the apparent quantum yield (AQY) of Ag 1 N 3 -HCNS is calculated to be about 23.6% at a monochromatic light of 420 nm (Figure 3b). Moreover, the photocatalytic stability of Ag 1 N 3 -HCNS was examined for 52 h with intermittent degassing of the reaction test every 4 h (Supporting Information Figure S10).…”