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Abstract The performance and reaction mechanism of a silver (Ag)-assisted one-dimensional NiTiO 3 nanorod/CN heterostructure nanocomposite (NTACN) photocatalyst for hydrogen (H 2) production were explored with simulated sunlight. The physicochemical properties of the synthesized catalysts were examined using various spectrophotometers. The newly developed NTACN samples displayed an enhanced photocatalytic activity in producing hydrogen. Specifically, the H 2 production rate of NTACN-5 (with a NT-to-ACN weight ratio of 5) was 3351 μmol/g-h, which was 1.42 times higher than that of ACN-4 with a Ag-to-CN ratio of 4 (2325 μmol/g-h). The effects of the Ag-to-CN and NiTiO 3 -to-ACN ratios on the photocatalytic activity of NTACN photocatalysts were determined. The NTACN photocatalysts exhibited a high long-term photostability under simulated sunlight irradiation. The increased photocatalyst performance and photostability were primarily ascribed to an improved charge separation efficiency due to a Z-scheme reaction mechanism as well as the assistance provided by Ag as a charge transfer shuttle and in the surface plasmon resonance effect. A photocatalytic mechanism for hydrogen generation over the NTACN photocatalysts under simulated sunlight irradiation is suggested. Graphical abstract Image 1 Highlights • Two visible light activated semiconductors were combined to develop Z-scheme catalyst. • Highly photostable Ag-assisted 1D NiTiO 3 /CN (NTACN) heterostructures were developed. • Active species test suggested that the NTACN composite follows a Z-scheme mechanism. • Enhanced charge separation was ascribed to Z-scheme mechanism and the role of Ag. • NTACN catalyst is efficiently applicable to sustainable production of green H 2 energy. [ABSTRACT FROM AUTHOR]

Abstract: Recent studies consider public R&D spending that affects abatement knowledge and endogenous growth, distortionary taxes that affect capital formation, pollution taxes that affect environmental degradation, and regeneration that restores natural capital. Our model combines all those elements. The combination affects prior results, focusing on two parameters: the need for distorting taxes, and productivity of abatement knowledge relative to pollution. First, these two extensions can reverse prior findings that pollution tax revenue is always enough to pay for public R&D. Second, tax distortions and externalities alter prior findings that the ratio of public to private capital depends only on output elasticities. Third, dynamics affect prior static findings about other public spending “crowding out” environmental public goods. Fourth, a greater need for public spending can lead to greater increases in distorting taxes or pollution taxes. Fifth, greater environmental regulation can mean growth is higher or lower, even if welfare is higher. [Copyright &y& Elsevier]