The majority of visible light-active plasmonic catalysts are often limited to Au, Ag, Cu, Al, etc., which have considerations in terms of costs, accessibility, and instability. Here, we show hydroxy-terminated nickel nitride (Ni3N) nanosheets as an alternative to these metals. The Ni3N nanosheets catalyze CO2 hydrogenation with a high CO production rate (1212 mmol g−1 h−1) and selectivity (99%) using visible light. Reaction rate shows super-linear power law dependence on the light intensity, while quantum efficiencies increase with an increase in light intensity and reaction temperature. The transient absorption experiments reveal that the hydroxyl groups increase the number of hot electrons available for photocatalysis. The in situ diffuse reflectance infrared Fourier transform spectroscopy shows that the CO2 hydrogenation proceeds via the direct dissociation pathway. The excellent photocatalytic performance of these Ni3N nanosheets (without co-catalysts or sacrificial agents) is suggestive of the use of metal nitrides instead of conventional plasmonic metal nanoparticles.

Establishment of an efficient and robust artificial photocatalytic system to convert solar energy into chemical fuels through CO2 conversion is a cherished goal in the fields of clean energy and environmental protection. In this work, we have explored an emergent low-Z nitrogen-rich carbon nitride material g-C3N5 (analogue of g-C3N4) for CO2 conversion under visible light illumination. A significant enhancement of the CH4 production rate was detected for g-C3N5 in comparison to that of g-C3N4. Notably, g-C3N5 also showed a very impressive selectivity of 100% toward CH4 as compared to 21% for g-C3N4. The photocatalytic CO2 conversion was performed without using sacrificial reagents. We found that 1% K doping in g-C3N5 enhanced its performance even further without compromising the selectivity. Moreover, 1% K-doped g-C3N5 also exhibited better photostability than undoped g-C3N5. We have also employed density functional theory calculation-based analyses to understand and elucidate the possible reasons for the better photocatalytic performance of K-doped g-C3N5.

The development of an active and competent catalyst for the conversion of carbon dioxide (CO2) to value added‐chemicals at low pressure and temperature have great importance in the field of industrial chemical production as well as in tackling global warming. In this report, nitridated dendritic fibrous nano‐silica (N‐DFNS) as highly porous and stable nano‐material have been synthesized by using ammonolysis reaction at various temperature ranging from 500–800 °C and used as heterogeneous catalysts in combination with TBAI for the synthesis of cyclic carbonates from CO2 and epoxide. The presence of high surface area balanced acid‐base bi‐functionalities generated on silica due to ammonolysis offered high activity towards the synthesis of cyclic carbonates at the atmospheric pressure with excellent recyclability.

Photocatalytic N2 fixation has emerged as one of the most useful ways to produce NH3, a useful asset for chemical industries and a carbon-free energy source. Recently, significant progress has been made toward designing efficient photocatalysts to achieve this objective. Here, we introduce a highly active type-II heterojunction fabricated via integrating two-dimensional (2D) nanosheets of exfoliated g-C3N5 with nickel–chromium layered double hydroxide (NiCr-LDH). With an optimized loading of NiCr-LDH on exfoliated g-C3N5, excellent performance is realized for green ammonia synthesis under ambient conditions without any noble metal cocatalyst(s). Indeed, the g-C3N5/NiCr-LDH heterostructure with 2 wt % of NiCr-LDH (CN-NCL-2) exhibits an ammonia yield of about 2.523 mmol/g/h, which is about 7.51 and 2.86 times higher than that of solo catalysts, i.e., NiCr-LDH (NC-L) and exfoliated g-C3N5 (CN-5), respectively, where methanol is used as a sacrificial agent. The enhancement of NH3 evolution by the g-C3N5/NiCr-LDH heterostructure can be attributed to the efficient charge transfer, a key factor to the photocatalytic N2 fixation rate enhancement. Additionally, N2 vacancies present in the system help adsorb N2 on the surface, which improves the ammonia production rate further. The best-performing heterostructure also shows long-term stability with the NH3 production rate remaining nearly constant over 20 h, demonstrating the excellent robustness of the photocatalyst.

We report a detailed study of hierarchically organized silica-Polyethylenimine (PEI) microspheres achieved through the evaporation-induced assembly. Due to complex interactions between oppositely-charged silica nanoparticles and PEI, non-monotonic jamming of the...