Graphitic carbon nitride-based photocatalysts in the applications of environmental catalysis

Semiconductor photocatalytic technology has shown great prospects in converting solar energy into chemical energy to mitigate energy crisis and solve environmental pollution problems.The key issue is the development of high-efficiency photocatalysts.Various strategies in the state-of-the-art advancements,such as heterostructure construction,heteroatom doping,metal/single atom loading,and defect engineering,have been presented for the graphitic carbon nitride(g-C3N4)-based nanocomposite catalysts to design their surface chemical environments and internal electronic structures to make them more suitable for different photocatalytic applications.In this review,nanoarchitecture design,synthesis methods,photochemical properties,potential photocatalytic applications,and related reaction mechanisms of the modified high-efficiency carbon nitride-based photocatalysts were briefly summarized.The superior photocatalytic performance was identified to be associated with the enhanced visible-light response,fast photoinduced electron-hole separation,efficient charge migration,and increased unsaturated active sites.Moreover,the further advance of the visible-light harvesting and solar-to-energy conversions are proposed.

Polymeric Carbon Nitride-based Single Atom Photocatalysts for CO_(2) Reduction to C1 Products

Photocatalytic CO_(2)reduction to C1 fuels is considered to be an important way for alleviating increasingly serious energy crisis and environmental pollution.Due to the environment-friendly,simple preparation,easy formation of highly-stable metal-nitrogen(M-Nx)coordination bonds,and suitable band structure,polymeric carbon nitride-based single-atom catalysts(C_(3)N_(4)-based SACs)are expected to become a potential for CO_(2)reduction under visible-light irradiation.In this review,we summarize the recent advancement on C_(3)N_(4)-based SACs for photocatalytic CO_(2)reduction to C1 products,including the reaction mechanism for photocatalytic CO_(2)reduction to C1 products,the structure and synthesis methods of C_(3)N_(4)-based SACs and their applications toward photocatalytic CO_(2)reduction reaction(CO_(2)RR)for C1 production.The current challenges and future opportunities of C_(3)N_(4)-based SACs for photoreduction of CO_(2)are also discussed.

Underwater wireless optical NOMA communication experiment system exploiting GaN-based micro-LED array grouping

This paper has proposed an experimental system for non-orthogonal multiple access(NOMA)wireless optical communication in challenging underwater turbulent environments,employing the gallium nitride(GaN)-based micro-LED array.This design of the GaN-based micro-LED array enables the independent transmission of signals from distinct data streams within the NOMA framework,facilitating direct optical power-domain superposition of NOMA signals.The experimental setup involves emulating oceanic turbulence channels,characterized by varying the level of scintillation intensity,to thoroughly investigate the bit error rate(BER)performance.The outcomes unequivocally demonstrate the superiority of our proposed NOMA scheme,as compared to conventional circuit-driven optical NOMA systems utilizing fixed LED array grouping,particularly in the presence of turbulent underwater channels.The proposed NOMA scheme exhibits consistently superior BER performance and maintains excellent linearity at the lower frequencies while effectively mitigating signal distortion at the higher frequencies.