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H2/CO2 cycle reaction activities of spinel structure NiFe2− x Cr x O4 ( x = 0, 0.08) prepared by co-precipitation were determined. The results showed that pure NiFe2O4 had almost lost its CO2 decomposition activities after 15 cycles, while Cr3+ doped NiFe2O4 still had about 40% of the initial reaction activity value after 50 reaction cycles. The magnetic properties of samples annealed at 350 °C indicated that M s and M r decreased from 32.49 to 26.04 emu/g and 9.39 to 7.31 emu/g, respectively, but H c increased from 230 to 1800 Oe with the increasing of Cr3+content. XRD Rietveld analysis showed that there appeared 23.15% Fe y Ni1− y (0< y < 1) and no Fe3C in pure NiFe2O4 system after the first H2/CO2 cycle reaction. With the increasing of cycle times, the phase abundance of NiFe2O4 decreased rapidly. At the same time, Fe3C appeared and its content increased fast. After 15 cycles, the phase abundance of NiFe2O4 is less than 5%wt, but those of Fe y Ni1− y (0 < y < 1) and Fe3C enhanced to 48.15 %wt and 46.92 %wt, respectively. However, the cycle reaction life of NiFe2− x Cr x O4 ( x = 0.08) was much longer than NiFe2O4. The spinel structure stability was improved dramatically because of the existing of Cr3+ in the cell of NiFe2O4. After 50 cycles, the phase abundance of NiFe2O4 still had 20 %wt. [ABSTRACT FROM AUTHOR]

Co-doped ceria of Ce1-aGda-ySmyO2-0.5a, wherein a=0.15 or 0.2, 0⩽y⩽a, were prepared for intermediate temperature solid oxide fuel cells (ITSOFCs). Their structures and ionic conductivities were characterized by X-ray diffraction and AC impedance spectroscopy. All the electrolytes were found to be ceria based solid solutions of fluorite type structures. However, co-doping effect was observed more apparent for the electrolytes with a=0.15 than for those with a=0.2. In comparison to the singly doped ceria, the co-doped ceria of Ce0.85Gd0.15-ySmyO1.925, wherein 0.05⩽y⩽0.1, showed much higher ionic conductivities at 773–973 K. These co-doped ceria are more ideal electrolyte materials of ITSOFCs. [Copyright &y& Elsevier]

The free torsion boundary integral equation is established using the Weighted Residual Method. The divergence free property of the boundary integrand is established. Evaluation of the warp function on the boundary is transformed into numerical evaluation of warp potential functions on the boundary of the free torsion pillar, with no singular numerical integrals. Copyright © 2003 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Abstract: Decomposition of CO2 over reduced MFe2O4 (M = Ni, Co, Cu, Zn) was studied by H2–TPR, H2–TG, and CO2–TG. XRD Rietveld analysis was used for determining phase composition and crystallite size of reduced and oxidized samples. The results indicate that spinel CoFe2O4 and CuFe2O4 are reduced to metals by H2, while ZnFe2O4 and NiFe2O4 only partly reduced at 350 °C. The CoFe2O4 spinel ferrite shows the best activity in decomposing CO2 and the ZnFe2O4 shows the best recovery ability in the process of redox. [Copyright &y& Elsevier]

Catalytic hydroxylation of 2,3,6-trimethylphenol with hydrogen peroxide over copper hydroxyphospate Cu2(OH)PO4 was studied. Catalytic data shows that the Cu2(OH)PO4 catalyst is active, giving the theoretical conversion at 40.2%. The main products in this reaction are trimethylhydroquinone and trimethylbenzoquinone; there is particularly high selectivity for trimethylhydroquinone. When the reaction is carried out in air, the selectivity for trimethylhydroquinone is at 72.2% and when the reaction is carried out under N2, the selectivity is at 94.7%. The other important factors associated with the catalytic properties have been investigated extensively. [Copyright &y& Elsevier]

The rise of CO 2 in the atmosphere, which results in severe climate change and temperature increase, is known as the major reason for the greenhouse effect. Reducing CO 2 to value-added products is an attractive solution to this severe problem, along with addressing the energy crisis, to which the catalysts being employed are of vital importance. Due to their high porosity and tunable compositions, metal-organic frameworks (MOFs) show great potential in energy conversion systems. By thermal or chemical treatment methods, the MOFs are easily turned into MOF-derived carbon nanomaterials. The much higher level of conductivity enables MOF-derived carbon nanomaterials to be employed in CO 2 conversion processes. The present review, discusses the state of the art of MOF-derived carbon nanomaterials in CO 2 electrochemical, photocatalytic, and thermal reduction applications. The corresponding reaction mechanisms and influence of various factors on catalyst performance are elaborated. Finally, the deficiencies and recommendations are provided for future progress., (Copyright © 2020 Xuan, Chen, Zhao, Yoon, Boczkaj and Sun.)