Photoreduction of CO 2 into solar fuels has received great interest, but suffers from low catalytic efficiency and poor selectivity. Herein, two single-Cuatom catalysts with unique Cu configurations in phosphorus-doped carbon nitride (PCN), namely, Cu 1 N 3 @PCN and Cu 1 P 3 @PCN were fabricated via selective phosphidation, and tested in visible light-driven CO 2 reduction by H 2 O without sacrificial agents. Cu 1 N 3 @PCN was exclusively active for CO production with a rate of 49.8 μmol CO g cat À 1 h À 1 , outperforming most polymeric carbon nitride (C 3 N 4 ) based catalysts, while Cu 1 P 3 @PCN preferably yielded H 2 . Experimental and theoretical analysis suggested that doping P in C 3 N 4 by replacing a corner C atom upshifted the d-band center
Carbon nanotube (CNT) films were one-step catalytically synthesized on silicon substrates by the premixed ethanol flame (PEF). Ferric nitrate and copper nitrate with diverse concentrations, as catalyst precursors, were respectively dissolved into the absolute ethanol to form PEF which could simultaneously offer heat source, carbon source and catalysts. More CNT films were synthesized on silicon substrates when first placed between the core and inner flame and then moved into location between the inner and outer flame. Scanning electron microscopy revealed that the morphologies of CNT films were greatly influenced by the catalyst precursors and locations of silicon substrates in PEF. CNT films synthesized by the copper nitrate PEF had a smaller tube diameter (~20 nm) and lower ratio of amorphous carbon (43.82%). The CNT yield increased along the concentration of catalyst precursors, but the graphitization degree decreased just the reverse. This approach had the potential of large-scale applications in solar cells and reinforced materials.
The in-plane thermoelectric generator (TEG) was ingeniously designed when the thermal gas flowed over the carbon nanotube (CNT) membrane at the modest speed of a few meters per second. It was composed of the glass substrate, aurum electrodes and CNT membrane synthesized by a floating catalyst chemical vapor deposition method. In the air under atmospheric pressure, the experimental results showed that the maximal output voltage could reach 1.7 mV. It related not only with the temperature difference between the hot-side and cold-side, but also the temperature gradient of the CNT membrane which was closely dependent on the velocity and temperature of the gas flow. The multi-physical power mechanism was applied to interpret the energy conversion, which included the coupling relation of the fluid dynamics, heat transmission and Seebeck effect. This novel method could effectively enhance the output voltage, extend the applied range of TEG and had a fine prospect.
A novel self-powered device based on the aligned carbon nanotube arrays (CNTA) in multi-physics fields has been put forward in this paper. Synthetically utilizing the photic, fluidic and thermic properties of carbon nanotubes, the multi-physical nanogenerators (MPNG) can generate electric currents when the solar irradiation and air flow synchronously effect on the material surface. Various MPNGs are connected in series to construct a unique truncated conus and cylinder shell structure in order to enhance the output voltage for self-powered electronic devices. The multi-physical power mechanism is formed by converting the solar and air flow energy to the thermoelectric effect. By the finite element analysis, the MPNG model including a pair of p-type and n-type CNTA elements is established, and its temperature and potential distribution are simulated. This self-powered device in multi-physics fields can be applied to a more complicated environment and has a fine prospect.
Photoreduction of CO2 into solar fuels has received great interest, but suffers from low catalytic efficiency and poor selectivity. Herein, two single‐Cu‐atom catalysts with unique Cu configurations in phosphorus‐doped carbon nitride (PCN), namely, Cu1N3@PCN and Cu1P3@PCN were fabricated via selective phosphidation, and tested in visible light‐driven CO2 reduction by H2O without sacrificial agents. Cu1N3@PCN was exclusively active for CO production with a rate of 49.8 μmolCO gcat−1 h−1, outperforming most polymeric carbon nitride (C3N4) based catalysts, while Cu1P3@PCN preferably yielded H2. Experimental and theoretical analysis suggested that doping P in C3N4 by replacing a corner C atom upshifted the d‐band center of Cu in Cu1N3@PCN close to the Fermi level, which boosted the adsorption and activation of CO2 on Cu1N3, making Cu1N3@PCN efficiently convert CO2 to CO. In contrast, Cu1P3@PCN with a much lower Cu 3d electron energy exhibited negligible CO2 adsorption, thereby preferring H2 formation via photocatalytic H2O splitting.
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