Photocatalytic CO₂ Reduction Enabled by Interfacial S-Scheme Heterojunction between Ultrasmall Copper Phosphosulfide and g-C₃N₄

Abstract

Transition metal phosphosulfides (TMPSs) have gained much interest due to their highly enhanced photocatalytic activities compared to their corresponding phosphides and sulfides. However, the application of TMPSs on photocatalytic CO2 reduction remains a challenge due to their inappropriate band positions and rapid recombination of photogenerated electron–hole pairs. Herein, we report ultrasmall copper phosphosulfide (us-Cu3P|S) nanocrystals anchored on 2D g-C3N4 nanosheets. Systematic studies on the interaction between us-Cu3P|S and g-C3N4 indicate the formation of an S-scheme heterojunction via interfacial P–N chemical bonds, which acts as an electron transfer channel and facilitates the separation and migration of photogenerated charge carriers. Upon the composite formation, the band structures of us-Cu3P|S and g-C3N4 are altered to enable the enhanced photocatalytic CO generation rate of 137 μmol g–1 h–1, which is eight times higher than that of pristine g-C3N4. The unique phosphosulfide structure is also beneficial for the enhanced electron transfer rate and provides abundant active sites. This first application of Cu3P|S to photocatalytic CO2 reduction marks an important step toward the development of TMPSs for photocatalytic applications.

S‐Scheme Photocatalytic Systems

“…Therefore, numerous S‐scheme photocatalysts for CO 2 reduction have been explored, e.g., g‐C 3 N 4 /Cu 3 P|S, g‐C 3 N 4 /Ti 3 C 2 T x Mxene, ZnMn 2 O 4 /ZnO, CdS/TiO 2 , g‐C 3 N 4 /CdSe‐DETA, g‐C 3 N 4 /Bi/BiVO 4 , g‐C 3 N 4 /Bi 12 O 17 C l2 , SnNb 2 O 6 /CdSe, TiO 2 @PDA, and BP/g‐C 3 N 4 . [ 61–71 ] Deng et al constructed hierarchical S‐scheme ZnMn 2 O 4 /ZnO nanofiber photocatalysts with using electrospinning and subsequent calcination. [ 62 ] The S‐scheme heterojunction photocatalysts present more than 4 times increment in CO and CH 4 products than pure ZnO nanofiber photocatalysts.…”

Energy Band Alignment and Redox‐Active Sites in Metalloporphyrin‐Spaced Metal‐Catechol Frameworks for Enhanced CO2 Photoreduction

“…[1] In response to these problems,much research has concentrated on exploring effective methods to achieve to convert CO 2 into value-added products driven by inexhaustible light, [2] which are also of paramount importance to the natural carbon balance.C onsidering the inherent chemical inertness of CO 2 ,aphotocatalyst is generally needed to accelerate the sluggish kinetics of CO 2 reduction. In recent decades,v arious photocatalysts for CO 2 reduction, including metals, [2e, 3] semiconductor-like metal oxides, [4] sulfides, [5] nitrides, [6] phosphides, [7] molecular complexes [8] have been examined. However,m ost of the reported photocatalysts for CO 2 reduction require ap hotosensitizer,c o-catalyst or sacrificial agent.…”

EPR Investigation on Electron Transfer of 2D/3D g‐C3N4/ZnO S‐Scheme Heterojunction for Enhanced CO2 Photoreduction

“…Pristine CN exhibits two diffraction peaks at 13.1 ° and 27.3 °, which are ascribed to the periodic packing of tri-s-triazine units and graphitic layers, respectively. [45,46] The XRD of the obtained CNZ hybrids showed characteristic peaks for CN and Z (ZnO peaks are marked with brown circle in Figure 2c), which assures the successful integration of CN with Z. The corresponding peaks of each component become weaker with decreasing the relative ratio of that component within the nanocomposite.…”