AuCu和石墨烯助催化剂协同增强氮化碳的光催化性能

Synergistic enhancement of photocatalytic performance of carbon nitride by AuCu and graphene cocatalysts

在热解法合成石墨相C_(3)N_(4)的基础上,先后采用溶剂热法和共沉淀法将石墨烯和AuCu双金属纳米颗粒负载到C_(3)N_(4)表面,得到AuCu/石墨烯/C_(3)N_(4)复合光催化剂。采用XRD、IR、BET、TEM、XPS、Absorption、PL、电化学等技术对AuCu/石墨烯/C_(3)N_(4)的结构进行分析,并详细评估其在可见光下分解水制氢和还原CO_(2)的性能。石墨烯的负载可以增加材料的比表面积,促进光生电荷的迁移。AuCu双金属以合金的形式负载于石墨烯/C_(3)N_(4)表面,平均粒径3.7nm。纳米Au的表面等离共振效应能拓宽材料的光谱吸收范围,而第二金属Cu的引入能加速光生电子的分离和传输。因此,石墨烯和AuCu双助催化剂的负载能显著增强C_(3)N_(4)的光催化性能。当AuCu的原子比为3:2、AuCu和石墨烯的负载量分别为0.5和1wt%时,得到的Au_(3)Cu_(2)/GC复合光催化剂表现出最佳的光催化性能,其分解水制氢的速率达到324.8μmol/h,光催化还原CO_(2)制取CH_(4)的活性和选择性分别为36.1μmol/hg和91.3%,并表现出良好的光催化稳定性。

On the basis of the pyrolysis synthesis of graphite C_(3)N_(4),graphene and AuCu bimetallic particles were successively depos-ited onto the surface of C_(3)N_(4) by solvothermal and coprecipitation methods to obtain AuCu/graphene/C_(3)N_(4) composite photocatalysts.The structure of AuCu/graphene/C_(3)N_(4) was analyzed using techniques such as XRD,IR,BET,TEM,XPS,Absorption,PL and elec-trochemistry.Photocatalytic performance over water spliting and CO_(2) reduction under visible light irradiation was evaluated.The loading of graphene can increase the specific surface area and promote the migration of photogenerated charges.The AuCu bimetallic particles was deposited on the surface of graphene/C_(3)N_(4) in the form of alloy structure with an average size of 3.7 nm.The surface plasmon resonance effect of Au nanoparticles can broaden the absorption range,while the doping of Cu can accelerate the separation and transportation of photogenerated electrons.Therefore,the loading of graphene and AuCu alloy dual cocatalysts can significantly enhance the photocatalytic performance of C_(3)N_(4).When the atomic ratio of AuCu was 3:2,and the loading amount of graphene and AuCu was 1.0 and 0.5 wt%,respectively,the obtained Au_(3)Cu_(2)/GC composite exhibited the optimal and stable photocatalytic per-formance.The hydrogen production rate from water was 324.8μmol/h.the activity and selectivity of photocatalytic reduction of CO_(2) to CH_(4) was 36.1μmol/hg and 91.3%.