Non-thermal plasma offers a route to synthesize ammonia from nitrogen and hydrogen at a low bulk-gas temperature and near-atmospheric pressure, with the operational flexibility needed for intermittent renewable electricity. Its principal challenge is not ammonia formation alone but the inefficient conversion of electrical energy into recoverable product. This review presents a reactor-centred interpretation of plasma catalysis. It first examines how electron-impact excitation, vibrationally excited nitrogen and radical chemistry establish a non-equilibrium reaction environment. It then considers how packed materials alter electric-field distribution, discharge mode, heat transfer and residence time while also supplying chemical sites for nitrogen adsorption and stepwise hydrogenation. Recent metal, support, defect and porous-material strategies are assessed in terms of these coupled physical and chemical roles. Particular attention is given to ammonia loss by plasma-induced decomposition and to reversible adsorption as a means of separating product formation from product recovery. The review argues that progress requires matched-power controls, complete nitrogen balances, energy yield reporting, transient measurements and long-duration testing. Rather than seeking a universally superior catalyst, future work should co-design the power supply, discharge geometry, accessible surface chemistry and product-removal step for a defined operating window. This paper provides discriminating criteria for delineating the boundary between "physical modification" and "chemical catalysis" in plasma catalysis, while offering a systematic attribution of the origins of energy yield discrepancies reported in the current literature.

Full-spectrum use of solar energy should be achieved efficiently to address the efficiency limitations of single photovoltaic (PV) or photothermal conversion. Spectral splitting technology splits sunlight into various bands and directs them to PV, photothermal and photochemical processes for cascade use. Based on the previous studies, this paper will systematically organize the theoretical foundation of full-spectrum utilization, review spectral splitting methods, discuss integration modes for multi-level synergistic systems, and explore application prospects in building integrated PV (BIPV) and ecological restoration. It also explores the main problems of optical efficiency, system integration and cost control, and puts forward some research directions. Research has shown that spectral-splitting multi-level synergistic systems are emerging as necessary directions for development, but new problems still need to be solved in splitter design, thermal management and life-cycle economic analysis. Future studies should integrate technical performance, economic feasibility, and environmental impacts into a unified life-cycle assessment framework to identify optimal system configurations. Overall, spectral-splitting multi-level synergistic systems represent a promising pathway toward full-spectrum solar energy utilization, but their practical development requires simultaneous improvements in optical components, thermal management, system integration, and economic performance.