Hierarchically Porous Polymeric Carbon Nitride as a Volume Photocatalyst for Efficient H₂ Generation under Strong Irradiation

Abstract

Generally, photocatalytic reaction efficiency decreases quickly with increasing irradiation intensity. Thus, it is a great challenge to achieve a high reaction efficiency under strong irradiation. Volume photocatalysis (VPs) is a new strategy for improving photocatalytic reaction efficiency. Herein, hierarchically porous polymeric carbon nitride (PCN) U‐PCN‐480 as a novel volume photocatalyst is fabricated by a template‐free pyrolysis of needle‐like urea. It is found for the first time that the hierarchical pore structure endows U‐PCN‐480 with the enhanced photoabsorption ability under strong irradiation. Consequently, Pt/U‐PCN‐480 displays excellent VPs activity for hydrogen evolution in the formic acid reaction system. Notably, the activity and apparent quantum efficiency (AQE) are significantly enhanced with increasing irradiation intensity, and the AQE reaches 62.7% and 70.4% at 400 and 380 nm with the irradiation intensity of 30.5 mW cm−2, respectively, the highest values among the reported data for PCN‐based photocatalysts. This effect of enhanced activity and AQE is the result of the synergy between VPs and the enhanced photoabsorption. The findings offer an approach to resolve the difficult problem of low photocatalytic reaction efficiency under strong irradiation and open a way to develop efficient photocatalyst materials and reaction systems.

Constructing novel hyper-crosslinked In2S3@HLZU-1 through molecular expansion for enhanced photocatalytic performance

“…All the results proved that the hyper-crosslinking treatment can improve the photocatalytic performance of LZU-1 materials, and the molecular expansion strategy can enhance bulk photocatalysis. 60,61 The possible mechanism of HLZU-1 in the degradation of TC is shown in Fig. 11.…”

Progress in Development of Photocatalytic Processes for Synthesis of Fuels and Organic Compounds under Outdoor Solar Light

“…However, occasionally, these values are used interchangeably . EQE values of current photocatalysts typically do not exceed 30% (visible light wavelengths ≤ 500 nm are usually used as a reference), − but there are a number of recent papers reporting promisingly high (>60%) efficiencies for hydrogen evolution. − …”

CoV-LDH and ZnxCd1–xS Solid-Solution Construct 0D/3D S-Scheme Heterojunction for Activated Solar Hydrogen Evolution

“…The addition of Zn reduces the toxicity of Cd and endows the Zn x Cd 1– x S solid solution with good performance and stability . Although the analogy of the Zn x Cd 1– x S solid solution and monometallic sulfide photocatalysis has some unique and obvious advantages, the Zn x Cd 1– x S solid solution still has shortcomings of small specific surface area and a high electron–hole recombination rate. − LDH has the advantages of tunable electronic structure, highly dispersed metal ions, interlayer exchangeable anions, and controllable topological transformation, which allows it to be used as an ideal photocatalyst. , Therefore, the Zn x Cd 1– x S solid solution is compounded with hydrotalcite to change the band structure of the composite material, thereby improving the ability of the material to absorb visible light …”

“…21−23 LDH has the advantages of tunable electronic structure, highly dispersed metal ions, interlayer exchangeable anions, and controllable topological transformation, which allows it to be used as an ideal photocatalyst. 24,25 Therefore, the Zn x Cd 1−x S solid solution is compounded with hydrotalcite to change the band structure of the composite material, thereby improving the ability of the material to absorb visible light. 26 CoV-LDH and Zn x Cd 1−x S were selected in this study to make the 0D Zn x Cd 1−x S solid solution and 3D CoV-LDH photocatalyst, which were combined to synthesize an efficient and stable S-scheme heterojunction composite photocatalyst CoV-LDH/Zn x Cd 1−x S. The synergistic effect of the two catalysts showed better catalytic performance and stimulated their respective advantages.…”