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Photocatalytic H2production viawater splitting has emerged as an eco-friendly and green technology to efficiently utilize solar energy. Developing visible light active photocatalysts, especially the metal-free ones, is crucial to access this technology considering their economic and environmental benefits. Hence, a facile UV reduction method was adopted to fabricate a highly active metal-free photocatalyst by modifying covalent triazine-based frameworks (CTFs) with reduced graphene oxide (rGO). The optimized CTF composite with 2 wt% rGO exhibited a 4.3-fold activity enhancement compared with pristine CTFs, showing a prime H2evolution efficiency of 894 μmol g−1h−1. The contributions of rGO to the photocatalytic system and the interaction between rGO and CTFs were thoroughly studied. The modification of rGO endowed the photocatalyst with improved visible-light absorption, stronger reductive ability, and faster separation rate of photoinduced carriers. Moreover, the covalent C–O–C bond formed in the two components facilitates the directional transfer of photoinduced electrons. A low-cost and robust photocatalyst for clean energy production is constructed in this work, providing inspirations for the design and fabrication of metal-free photocatalytic materials with superior performance.

Seeking efficient visible-light-driven photocatalysts for water splitting to produce H2has attracted much attention. Chemical doping is an effective strategy to enhance photocatalytic performance. Herein, we reported phosphorus-doped covalent triazine-based frameworks (CTFs) for photocatalytic H2evolution. Phosphorus-doped CTFs were fabricated by a facile thermal treatment using easily available red phosphorus as the external phosphorus species. The introduction of phosphorus atoms into the frameworks modified the optical and electronic property of CTFs, thus promoting the generation, separation, and migration of photoinduced electron–hole pairs. Consequently, the photocatalytic H2-production efficiency of phosphorus-doped CTFs was greatly improved, which was 4.5, 3.9, and 1.8 times as high as that of undoped CTFs and phosphorus-doped g-C3N4calcined from melamine and urea, respectively.

Recently, highly efficient activation of peroxymonosulfate (PMS) by S-doped cobalt-based catalysts are receiving increased attention. The effect of S is worth exploring since it has a great influence on PMS activation performance. In this work, dimethyl sulfoxide was adopted as an S source and loaded on bamboo biochar (BB) with Co to form CoS/BBC, which served as an efficient catalyst for PMS activation to degrade sulfamethoxazole (SMX). The experiment results showed that CoS/BBC exhibits an excellent catalytic activity and the SMX (20 mg/L) can be completely degraded under the attack of species of ·OH, SO4-·, 1O2and electron transfer. The SMX degradation conformed to pseudo first-order kinetics with rate constant reaching 0.442 min−1in 10 min under the optimal conditions (a catalyst dose of 0.02 g/L, a PMS dose of 0.3 g/L and an initial pH = 7.0). The electrochemical experiments and density functional theory (DFT) calculation revealed that the introduction of S can accelerate electron transfer and promote the decomposition of PMS while facilitating Co(III)/Co(II) redox cycling. Furthermore, liquid chromatograph-mass spectrometer (LC-MS) and ecological structure activity relationships (ECOSAR) proved that the degradation process of SMX in CoS/BBC/PMS system has low ecotoxicity and is harmless to the environment. This work provides a new strategy for enhancing electron transfer by S-doped metal materials and the synthesis of efficient catalysts for SMX removal.