Nature Communications
·
2024
·Vol. 15
·期 1
·1-12
·
IF 14.7
He Tiwei,Tang Hongchao,Wu Jie,Wang Jiaxuan,Zhang Mengling,Lu Cheng,Huang Hui,Zhong Jun,Cheng Tao,Liu Yang,Kang Zhenhui
Carbon-based metal-free catalysts are promising green catalysts for photocatalysis and electrocatalysis due to their low cost and environmental friendliness. A key challenge in utilizing these catalysts is identifying their active sites, given their poor crystallinity and complex structures. Here we demonstrate the key structure of the double-bonded conjugated carbon group as a metal-free active site, enabling efficient O 2 photoreduction to H 2 O 2 through a cascaded water oxidation − O 2 reduction process. Using ethylenediaminetetraacetic acid as a precursor, we synthesized various carbon-based photocatalysts and analyzed their structural evolution. Under the polymerization conditions of 260 °C to 400 °C, an N -ethyl- 2 -piperazinone-like structure was formed on the surface of the catalyst, resulting in high photocatalytic H 2 O 2 photoproduction (2884.7 μmol g −1 h −1 ) under visible light. A series of control experiments and theoretical calculations further confirm that the double-bond conjugated carbonyl structure is the key and universal feature of the active site of metal-free photocatalysts.
研究领域:
材料科学
·
催化
·
光化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2024
·
IF 20.2
Lin Wang,Hao Jiang,Jun Zhang,Xinhua He,Fangfang Li,Jing Feng,Bo Pan
Dissolved black carbon (DBC) can generate reactive oxygen species (ROS), playing significant roles in contaminants degradation and chemical stresses to microorganisms. However, little is known regarding the photoproduction sites to ROS generation, mainly because of its extremely complicated composition. Herein, the ROS generation and photoexcited alteration of DBC were investigated. The generation mechanisms of hydroxyl radical (•OH), superoxide anion (O 2 •− ) and singlet oxygen ( 1 O 2 ) were inferred by employing various model chemicals. Results showed that the photo-excited aliphatic carbonyls greatly contributed to ∙OH, O 2 •− , and 1 O 2 generation. Ether groups were identified as the main structural source of H 2 O 2 -dependent ∙OH generation. The novel non-electron transfer process involved carbonyl, ether, alcohol, and ester groups to produce O 2 •− was proposed. These findings reveal the vital role of oxygenated functional groups within DBC in the photoactive generation of ROS, and thus provides new theoretical information for DBC’s environmental geochemical behavior.
研究领域:
环境科学
·
化学
·
地球化学
✓ 已验证
产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2024
·
IF 20.2
Zenan Li,Jiacheng Li,Jiaxuan Wang,Luhan Li,Weijie Yuan,Tianyang Zhang,Jian Shen,Yurong Ma,Zhenglong Fan,Fan Liao,Hui Huang,Yang Liu,Zhenhui Kang
Understanding photocatalytic processes of nanoclusters at the nanoscale remains a challenge. Here, we synthesized two kinds of gold nanoclusters stabilized by thiol ligands (AuNCs) and carbon dots (AuCDs) to study their interfacial kinetics in photocatalytic H 2 O 2 production. Three operando testing methods, including transient photovoltage (TPV), transient potential scanning (TPS) and photo-induced current (TPC), are used to investigate the influence of carbon dots (CDs) on catalytic processes. While AuNCs and AuCDs show similar O 2 adsorption abilities, AuCDs exhibit a lower reaction rate due to less surface effective photoelectrons. The AuNCs utilize their own ligands to consume photo-generated holes while the presence of CDs in AuCDs changes this way and providing stable catalytic sites for water oxidation reaction. Additionally, with the addition of CDs, the oxygen reduction reaction pathway changes from a two-step one electron process to a one-step two electron process. This work provides new insights for understanding the photocatalytic processes.
研究领域:
材料科学
·
纳米技术
·
光化学
·
催化
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2022
·
IF 9.965
Kaiqiang Wei,Haodong Nie,Yi Li,Xiao Wang,Yan Liu,Yajie Zhao,Hong Shi,Hui Huang,Yang Liu,Zhenhui Kang
Artificial photoproduction of hydrogen peroxide (H 2 O 2 ) from H 2 O and O 2 by metal-free catalysts (e.g., graphitic carbon nitride) is regarded as an ultra-clean approach. Metal-free catalysts are often hindered by unpropitious rapid charge recombination and unfavorable selectivity. Herein, three carbon dots (CDs1 to CDs3) decorated modified-carbon nitride (CDs1-NCN, CDs2-NCN and CDs3-NCN) were designed and fabricated, which show diverse activity of H 2 O 2 photoproduction. Among them, CDs1-NCN, as a two-channel photocatalyst, achieves H 2 O 2 production with high efficiency (1938 μmol h −1 g −1 ). This process is at normal pressure and without sacrificial agent under visible region ( λ ≥ 420 n m ) , which is 27.5- times higher than that of pristine C 3 N 4 . The apparent quantum efficiency can be calculated to 7.03 % ( λ = 365 n m ) . In this system, CDs with different energy levels dominate the activity of metal-free catalyst for hydrogen peroxide photoproduction. Combining with photoelectrochemical test and transient photovoltage analysis, the active site and the catalytic mechanism of these composite catalysts are also clarified. Our work provides a clearly insight for understanding of the regulation of interfacial electron transport in metal-free photocatalysts.
研究领域:
材料科学
·
化学
·
催化
·
光化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Materials Advances
·
2022
·Vol. 3
·期 10
·4243-4251
·
IF 0
Qiang Hong,Qingyao Wu,Zhenyu Wu,Yan Liu,Yi Li,Hui Huang,Yang Liu,Zhenhui Kang
Metal-free polymer-based catalysts have shown promising photocatalytic performance for efficient hydrogen peroxide (H2O2) photoproduction under visible light. However, the structure of the active site and the interface charge transfer of these catalysts have not been revealed clearly. Here, we report the fabrication of four narrow bandgap single-dye-based polymer metal-free catalysts (PPC-X, X = 75, 100, 125, 175). The catalyst PPC-X was synthesized by a hydrothermal method using proanthocyanidin (OPC) as the raw material. The reaction temperature was set at 75 °C, 100 °C, 125 °C, and 175 °C, and finally, the single-dye polymer catalyst was obtained, which was marked as PPC-X, with X representing the polymerization temperature. The PPC-X as catalysts show diverse catalytic behavior for H2O2 photoproduction. Under visible light excitation, the PPC-X catalysts (X = 100, 125, 175) reduced O2 to produce H2O2via the two-electron transfer pathway and oxidized water to release O2 by the four-electron transfer pathway. For the PPC-75 catalyst, O2 was reduced by photo-generated electrons on the catalyst surface via the two-electron transfer pathway, while the PPC-75 catalyst itself also serves as a sacrificial agent to consume the photo-generated holes, leading to a high H2O2 production. The H2O2 yield of PPC-75 is 1152 μmol g−1 h−1, and that of PPC-100 is up to 1214 μmol g−1 h−1 at a light intensity of 32.6 mW cm−2. This work provides a practical research example and idea for the in-depth understanding and design of efficient polymer-based photocatalysts.
研究领域:
材料科学
·
化学
·
催化
·
光化学
✓ 已验证
产品关联
DOI
ACS Applied Materials & Interfaces
·
2023
·
IF 9.5
Qiushi Hu,Yuling Huang,Xuemeng Yu,Shaokuan Gong,Yifan Wen,Yong Liu,Geng Li,Qiang Zhang,Ruquan Ye,Xihan Chen
Solar-driven photocatalysis is a promising approach for renewable energy application. H2O2 photocatalysis by metal-free graphitic carbon nitride has been gaining attention. Compared with traditional thermal catalysis, metal-free graphitic carbon nitride photocatalysis could lower material cost and achieve greener production of H2O2. Also, to better guide photocatalyst design, a fundamental understanding of the reaction mechanism is needed. Here, we develop a series of model cost-effective metal-free H2O2 photocatalysts made from graphitic carbon nitride (melem) and common imide groups. With 4,4′-oxydiphthalic anhydride (ODPA)-modified g-C3N4, a H2O2 yield rate of 10781 μmol/h·g·L could be achieved. Transient absorption and ex situ Fourier transform infrared (FTIR) measurements revealed an ultrafast charge transfer from the melem core to water with ∼3 ps to form unique N–OH intermediates. The electron withdrawing ability of the anhydride group plays a role in governing the rate of electron transfer, ensuring efficient charge separation. Our strategy represents a new way to achieve a low material cost, simple synthesizing strategy, good environment impact, and high H2O2 production for renewable energy application.
研究领域:
材料科学
·
化学
·
可再生能源
·
催化
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）