Huayu Chen

Bio: Huayu Chen is an academic researcher from Chinese Ministry of Education. The author has contributed to research in topics: Photocatalysis. The author has an hindex of 2, co-authored 2 publications receiving 7 citations.

Enhanced Photocatalytic CO2 Reduction over TiO2 Using Metalloporphyrin as the Cocatalyst

Abstract: The photocatalytic reduction of carbon dioxide (CO2) into CO and hydrocarbon fuels has been considered as an ideal green technology for solar-to-chemical energy conversion. The separation/transport of photoinduced charge carriers and adsorption/activation of CO2 molecules play crucial roles in photocatalytic activity. Herein, tetrakis (4-carboxyphenyl) porphyrin (H2TCPP) was incorporated with different metal atoms in the center of a conjugate macrocycle, forming the metalloporphyrins TCPP-M (M = Co, Ni, Cu). The as-obtained metalloporphyrin was loaded as a cocatalyst on commercial titania (P25) to form TCPP-M@P25 (M = Co, Ni, Cu) for enhanced CO2 photoreduction. Among all of the TCPP-M@P25 (M = Co, Ni, Cu), TCPP-Cu@P25 exhibited the highest evolution rates of CO (13.6 μmol⋅g−1⋅h−1) and CH4 (1.0 μmol⋅g−1⋅h−1), which were 35.8 times and 97.0 times those of bare P25, respectively. The enhanced photocatalytic activity could be attributed to the improved photogenerated electron-hole separation efficiency, as well as the increased adsorption/activation sites provided by the metal centers in TCPP-M (M = Co, Ni, Cu). Our study indicates that metalloporphyrin could be used as a high-efficiency cocatalyst to enhance CO2 photoreduction activity.

Porphyrins and phthalocyanines as biomimetic tools for photocatalytic H2 production and CO2 reduction.

Abstract: The increasing energy demand and environmental issues caused by the over-exploitation of fossil fuels render the need for renewable, clean, and environmentally benign energy sources unquestionably urgent. The zero-emission energy carrier, H2 is an ideal alternative to carbon-based fuels especially when it is generated photocatalytically from water. Additionally, the photocatalytic conversion of CO2 into chemical fuels can reduce the CO2 emissions and have a positive environmental and economic impact. Inspired by natural photosynthesis, plenty of artificial photocatalytic schemes based on porphyrinoids have been investigated. This review covers the recent advances in photocatalytic H2 production and CO2 reduction systems containing porphyrin or phthalocyanine derivatives. The unique properties of porphyrinoids enable their utilization both as chromophores and as catalysts. The homogeneous photocatalytic systems are initially described, presenting the various approaches for the improvement of photosensitizing activity and the enhancement of catalytic performance at the molecular level. On the other hand, for the development of the heterogeneous systems, numerous methods were employed such as self-assembled supramolecular porphyrinoid nanostructures, construction of organic frameworks, combination with 2D materials and adsorption onto semiconductors. The dye sensitization on semiconductors opened the way for molecular-based dye-sensitized photoelectrochemical cells (DSPECs) devices based on porphyrins and phthalocyanines. The research in photocatalytic systems as discussed herein remains challenging since there are still many limitations making them unfeasible to be used at a large scale application before finding a large-scale application.

A Review on MXene Synthesis, Stability, and Photocatalytic Applications.

Abstract: Photocatalytic water splitting, CO2 reduction, and pollutant degradation have emerged as promising strategies to remedy the existing environmental and energy crises. However, grafting of expensive and less abundant noble-metal cocatalysts on photocatalyst materials is a mandatory practice to achieve enhanced photocatalytic performance owing to the ability of the cocatalysts to extract electrons efficiently from the photocatalyst and enable rapid/enhanced catalytic reaction. Hence, developing highly efficient, inexpensive, and noble-metal-free cocatalysts composed of earth-abundant elements is considered as a noteworthy step toward considering photocatalysis as a more economical strategy. Recently, MXenes (two-dimensional (2D) transition-metal carbides, nitrides, and carbonitrides) have shown huge potential as alternatives for noble-metal cocatalysts. MXenes have several excellent properties, including atomically thin 2D morphology, metallic electrical conductivity, hydrophilic surface, and high specific surface area. In addition, they exhibit Gibbs free energy of intermediate H atom adsorption as close to zero and less than that of a commercial Pt-based cocatalyst, a Fermi level position above the H2 generation potential, and an excellent ability to capture and activate CO2 molecules. Therefore, there is a growing interest in MXene-based photocatalyst materials for various photocatalytic events. In this review, we focus on the recent advances in the synthesis of MXenes with 2D and 0D morphologies, the stability of MXenes, and MXene-based photocatalysts for H2 evolution, CO2 reduction, and pollutant degradation. The existing challenges and the possible future directions to enhance the photocatalytic performance of MXene-based photocatalysts are also discussed.

Efficient photocatalytic hydrogen evolution coupled with benzaldehyde production over 0D Cd0.5Zn0.5S/2D Ti3C2 Schottky heterojunction

Abstract: Abstract Converting water into hydrogen fuel and oxidizing benzyl alcohol to benzaldehyde simultaneously under visible light illumination is of great significance, but the fast recombination of photogenerated carriers in photocatalysts seriously decreases the conversion efficiency. Herein, a novel dual-functional 0D Cd 0.5 Zn 0.5 S/2D Ti 3 C 2 hybrid was fabricated by a solvothermally in-situ generated assembling method. The Cd 0.5 Zn 0.5 S nano-spheres with a fluffy surface completely and uniformly covered the ultrathin Ti 3 C 2 nanosheets, leading to the increased Schottky barrier (SB) sites due to a large contact area, which could accelerate the electron-hole separation and improve the light utilization. The optimized Cd 0.5 Zn 0.5 S/Ti 3 C 2 hybrid simultaneously presents a hydrogen evolution rate of 5.3 mmol/(g·h) and a benzaldehyde production rate of 29.3 mmol/(g·h), which are ∼3.2 and 2 times higher than those of pristine Cd 0.5 Zn 0.5 S, respectively. Both the multiple experimental measurements and the density functional theory (DFT) calculations further demonstrate the tight connection between Cd 0.5 Zn 0.5 S and Ti 3 C 2 , formation of Schottky junction, and efficient photogenerated electron—hole separation. This paper suggests a dual-functional composite catalyst for photocatalytic hydrogen evolution and benzaldehyde production, and provides a new strategy for preventing the photogenerated electrons and holes from recombining by constructing a 0D/2D heterojunction with increased SB sites.