This review highlights the recent progress in the production of hydrogen using a metal oxynitride photocatalyst under visible light irradiation.

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Summary Compared with traditional photovoltaic‐thermal system, low concentration photovoltaic‐thermal systems install the low‐power concentrator (compound parabolic concentrator, Fresnel concentrator, miniature trough concentrator, etc) to improve system performance. In this paper, a baffle heat exchange channel was designed, which can decrease the temperature gradient of low concentration photovoltaic‐thermal module in the flow direction, based on the traditional flat‐box photovoltaic‐thermal collector. The system performance was monitored with different baffle spacing, flow rate, inlet temperature, ambient temperature, and radiation intensity by adopting simulation methodology. Furthermore, an experiment was performed to validate and evaluate the simulation results. The results indicated that, on a typical day, the maximum of thermal efficiency and electrical efficiency of the module were 55.11% and 12.50%, respectively.

The soil organic carbon accumulation in soda saline-alkaline soil and the humus composition changes with application of aluminum sulfate and rice straw were investigated by the controlled simulative experiments in laboratory. For evaluating the amelioration effect, organic carbon content and humus composition in soda saline-alkaline soil were investigated with different application amounts of rice straw and aluminum sulfate. Potassium dichromate oxidation titration (exogenous heat) method and Kumada method were used to analyze the contents of organic carbon and humus composition, respectively. The transformation of soil organic matter in the saline-alkali soil during the amelioration has been clarified in this paper. The results demonstrated that the contents of soil organic carbon were significantly increased (13-92%) with different application amounts of rice straw and aluminum sulfate. The contents of free fraction and combined fraction of humus and their compositions (humic acid and fulvic acid) were increased with different application amounts of rice straw. The free fraction of humus was increased more dramatically. Due to aluminum sulfate application, free fraction of humus and humic acid (HA) was transformed to combined fraction partially. Free HA was changed to be P type with rice straw application. With aluminum sulfate application, free form of HA was changed from type P to type Rp. For rice straw application, combined HA only was transferred within the area of type A. Aluminum sulfate addition had no significant effect on the type of combined form of HA. With the same amount of rice straw application, the contents of soil organic carbon were increased by increasing the amount of aluminum sulfate application. Both rice straw and aluminum sulfate applications could reduce the humification degree of free and combined fraction of HA. According to the types of HA, it could be concluded that humus became younger and renewed due to the application of rice straw and aluminum sulfate.