Zhichao Yu,Xin Liu,Yang Liu,Yuan Li,Zhuohan Zhang,Kangli Chen,Shumin Han
Multiple catalysts have exhibited high activity on improving the hydrogen storage performance of MgH 2 . Herein, the hydrogen ab/desorption kinetics of MgH 2 is significantly improved by using Ni@C@CeO 2 as the catalyst. The results show that 10 wt%-Ni@C@CeO 2 doped MgH 2 can absorb 4.51 wt% hydrogen within 60 min under low temperature 75 °C. Furthermore, the MgH 2 -Ni@C@CeO 2 composites release approximately 4.88 wt% H 2 within 10 min at 325 °C. Moreover, the composites show excellent cycling performance, with negligible decrease in hydrogen storage capacity, hydrogen uptake rate and hydrogen release rate after ten cycles at 350 °C. The Rietveld refinement of X-ray diffraction and transmittance electron microscopy measurements reveal that Mg 2 NiH 4 /Mg 2 Ni and CeH 2.73 phases are in-situ formed. The mutual conversion of “Mg 2 Ni/Mg 2 NiH 4 ” during hydrogen ab/desorption is a well-known “hydrogen pump” effect, which improvs the hydrogen storage performance of MgH 2 . The presence of CeH 2.73 accelerate the conversion of Mg 2 Ni/Mg 2 NiH 4 , which we call ‘facilitated hydrogen pump’ effect. This attempt paves a potential way to achieve high performance Mg-based composites hydrogen storage materials via collaborative action between Ni and Ce species.
The one-step hydrothermal reconstruction of bioethanol into higher alcohols represents a pivotal advancement in green chemistry, addressing both environmental sustainability and energy regeneration. Herein, a rational design of Ni@C-CeO2 catalysts via a sol–gel method for efficient aqueous-phase ethanol C–C coupling was reported. Systematic investigation of Ni loading and precursor carbonization temperature revealed their critical roles in modulating catalyst microstructure and performance. The optimized Ni-2@C-CeO2-500 catalyst demonstrated exceptional activity under 190 °C and 12 h, achieving ethanol conversion of 72.0% and C4+ alcohol yield of 55.6%. Advanced characterization techniques unveiled structure-performance relationships: (1) controlled Ni loading ensured optimal nanoparticle dispersion, while excessive loading induced aggregation; (2) carbonization at 500 °C balanced carbon matrix architecture and CeO2 reducibility. XPS analysis revealed that oxygen vacancy concentration critically modulates strong metal–support interactions through Ce3+-induced charge redistribution, facilitating interfacial electron transfer during reaction. Furthermore, the Ni-2@C-CeO2-500 catalyst demonstrated excellent stability with sustained activity retention over five consecutive cycles. This work establishes a renewable and technologically viable alternative to conventional petroleum-derived chemicals widely utilized in the chemical industry, demonstrating significant potential for applications in green and sustainable chemistry.
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