This content will become publicly available on April 5, 2023
- Publication Date:
- NSF-PAR ID:
- Journal Name:
- Journal of Materials Chemistry A
- Page Range or eLocation-ID:
- 7896 to 7910
- Sponsoring Org:
- National Science Foundation
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Integrating photocatalysis and thermocatalysis to enable efficient CO2 reforming of methane on Pt supported CeO2 with Zn doping and atomic layer deposited MgO overcoatingCO2 reforming or dry reforming of methane (DRM) produces syngas with a low carbon footprint, but the efficiency and stability of DRM remains a challenge. Herein, we report an efficient photo-thermo-chemical DRM (PTC-DRM) process on a Pt supported CeO2 catalyst with Zn doping and surface atomic layer deposition (ALD)-enabled MgO overcoating using concentrated sunlight as the energy input. Under 30 suns irradiation at 600 °C, high syngas production rates of 356 and 516 mmol g−1 h−1 for H2 and CO are achieved, which are more than 9 and 3 times larger than those obtained in the thermally driven DRM. Moreover, the light illumination stabilizes the dry reforming process without deactivation, which results from the in situ generation of oxygen vacancy on CeO2 by photo-induced electrons that enables stable CO2 thermo-activation. The ALD coating also reduces surface charge recombination through passivating surface states, thereby enhancing photocatalytic activity.
A thermo-photo hybrid process for steam reforming of methane: highly efficient visible light photocatalysisSteam reforming of methane (SRM) is one of the most important industrial processes, which produces 95% of hydrogen used in the USA. However, SRM is an endothermic reaction, which requires a high energy input and a high reaction temperature (>800 °C) for the current process. Furthermore, its products must be subjected to a water–gas shift (WGS) process. A photocatalytic process is expected to solve the energy issue and to eliminate the necessity of WGS for SRM. However, the hydrogen yield from the current photocatalytic steam reforming of methane (PSRM) is very low (μmol h −1 g −1 level), which is far below industrial interest. This work demonstrates that a Pt/blackTiO 2 catalyst dispersed on a light-diffuse-reflection-surface is excellent for efficient visible-light PSRM. Under visible light illumination on the catalyst by filtering UV light from AM 1.5G sunlight, CH 4 and H 2 O were directly converted into H 2 and CO 2 without WGS, leading to a high H 2 yield of 185 mmol h −1 g −1 with a quantum efficiency of 60% at 500 °C. The yield is 3 orders of magnitude larger than the reported values, which can be attributed to the synergistic effect between potential andmore »
Ce stabilized Ni–SrO as a catalytic phase transition sorbent for integrated CO 2 capture and CH 4 reformingIntegration of carbon dioxide capture from flue gas with dry reforming of CH 4 represents an attractive approach for CO 2 utilization. The selection of a suitable bifunctional material serving as a catalyst/sorbent is the key. This paper reports Ni decorated and CeO x -stabilized SrO (SrCe 0.5 Ni 0.5 ) as a multi-functional, phase transition catalytic sorbent material. The effect of CeO x on the morphology, structure, decarbonation reactivity, and cycling stability of the catalytic sorbent was determined with TEM-EDX, XRD, in situ XRD, CH 4 -TPR and TGA. Cyclic process tests were conducted in a packed bed reactor. The results indicate that large Ni clusters were present on the surface of the SrNi sorbent, and the addition of CeO 2 promoted even distribution of Ni on the surface. Moreover, the Ce–Sr interaction promoted a complex carbonation/decarbonation phase-transition, i.e. SrCO 3 + CeO 2 ↔ Sr 2 CeO 4 + CO 2 as opposed to the conventional, simple carbonation/decarbonation cycles ( e.g. SrCO 3 ↔ SrO + CO 2 ). This double replacement crystalline phase transition mechanism not only adjusts the carbonation/calcination thermodynamics to facilitate SrCO 3 decomposition at relatively low temperatures but also inhibits sorbent sintering. As amore »
Constructing single atom catalysts with fine-tuned coordination environments can be a promising strategy to achieve satisfactory catalytic performance. Herein, via a simple calcination temperature-control strategy, CeO2supported Pt single atom catalysts with precisely controlled coordination environments are successfully fabricated. The joint experimental and theoretical analysis reveals that the Pt single atoms on Pt1/CeO2prepared at 550 °C (Pt/CeO2-550) are mainly located at the edge sites of CeO2with a Pt–O coordination number of
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Alkaline thermal treatment of seaweed for high-purity hydrogen production with carbon capture and storage potential
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