Catalytic CO2 reforming of CH4 (CRM) to produce syngas (H2 and CO) provides a promising approach to reducing global CO2 emissions and the extensive utilization of natural gas resources. However, the rapid deactivation of the reported catalysts due to severe carbon deposition at high reaction temperatures and the large energy consumption of the process hinder its industrial application. Here, a method for almost completely preventing carbon deposition is reported by modifying the surface of Ni nanocrystals with silica clusters. The obtained catalyst exhibits excellent durability for CRM with almost no carbon deposition and deactivation after reaction for 700 h. Very importantly, it is found that CRM on the catalyst can be driven by focused solar light, thus providing a promising new approach to the conversion of renewable solar energy to fuel due to the highly endothermic characteristics of CRM. The reaction yields high production rates of H2 and CO (17.1 and 19.9 mmol min−1 g−1, respectively) with a very high solar‐to‐fuel efficiency (η, 12.5%). Even under focused IR irradiation with a wavelength above 830 nm, the η of the catalyst remains as high as 3.1%. The highly efficient catalytic activity arises from the efficient solar‐light‐driven thermocatalytic CRM enhanced by a novel photoactivation effect.
TiO 2 /CeO 2 nanocomposites of anatase TiO 2 nanoparticles supported on microsized mesoporous CeO 2 were prepared and characterized by SEM, TEM, BET, XRD, Raman, XPS, and diffuse reflectance UV−vis absorption. The formation of the TiO 2 /CeO 2 nanocomposites considerably enhances their catalytic activity for the gas-phase oxidation of benzene, one of the hazardous volatile organic compounds (VOCs), under the irradiation of a Xe lamp compared to pure CeO 2 and TiO 2 . A solar-light-driven thermocatalysis on CeO 2 is found for the TiO 2 /CeO 2 nanocomposites. There is a synergetic effect between the photocatalysis on TiO 2 and the thermocatalysis on CeO 2 for the TiO 2 /CeO 2 nanocomposites, which significantly increases their catalytic activity. The CO 2 formation rate (r CO2 ) of the TiO 2 /CeO 2 nanocomposite with the Ti/Ce molar ratio of 0.108 under the synergetic photothermocatalytic condition is 36.4 times higher than its r CO 2 under the conventional photocatalytic condition at near room temperature. CO temperature-programmed reduction (CO-TPR) with the irradiation of the Xe lamp and in the dark reveals that the synergetic effect, which occurs at the interface of the TiO 2 /CeO 2 nanocomposite, is due to the considerable promotion of the CeO 2 reduction by the photocatalysis on TiO 2 .
It is urgent to explore
cost-effective, high-efficiency, and durable
electrocatalysts for electrochemical water splitting due to the rapidly
increasing energy consumption. In this work, we successfully synthesize
Ca-doped CuCoO2 nanosheets (CCCO-P NSs) with different
Ca2+ dopants (such as 3, 5, and 10 atom %) by a surfactant-modified
hydrothermal reaction with polyvinylpyrrolidone (PVP) addition. The
oxygen evolution reaction (OER) performances of these CCCO-P NSs in
1.0 M KOH are investigated. An optimal nickel foam supported CCCO-P2
NSs (Ni@CCCO-P2, 5 atom % Ca-doped) electrode requires low overpotential
of 470 mV to afford the current density of 10 mA cm–2 and small Tafel slope of 96.5 mV dec–1. Furthermore,
the Ni@CCCO-P2 electrode displays outstanding long-term stability
during the galvanostatic OER electrolysis for 18 h with a little degradation
of 32 mV. The improvement of OER performances for CCCO-P2 NSs could
be attributed to their higher active surface area, more active sites
(Co vacancies defect and Co3+/Co4+ redox pairs),
and higher electrical conductivity. This work highlights the joint
effect of surfactant and Ca doping for preparing CuCoO2 with nanosheet-like morphology and porous crystal structure, which
is favorable for enhancing their OER performance.
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