Effect of Modified Alumina Support on the Performance of Ni-Based Catalysts for CO2 Reforming of Methane

Abstract

The CO2 reforming of methane to syngas was examined over five different supported catalysts. In this study, 5% Ni was used as the active metal part of the catalyst. To better comprehend the impact of the supports on the catalytic properties, 5% Ni-based catalysts were characterized using nitrogen adsorption–desorption isotherms, XRD, H2-TPR, CO2-TPD, TGA, TPO, FTIR, and Raman. The results showed that the catalyst support with the highest surface area provided the best catalytic activity. The acquired CH4 and CO2 conversions at 700 °C were 58.2% and 67.6%, respectively, with a hydrogen/carbon ratio of 0.85. The TGA investigation of the high-surface-area sample produced a minimum carbon deposition of 11.2 wt.%, and in the CO2-TPD investigation, the high-surface-area sample exhibited the absence of a peak in the strong-basic-sites zone. The formation of NiAl2O4 spinel, moderate basicity, and the high surface area explained the outperformance of the high-surface-area catalyst sample.

Ni–Ca–Al Synergistic Effect in Dual-Function Materials for Integrated CO2 Capture and Conversion

“…As shown in Figure , for the Al-modified materials (Ni/AlCaO x , AlCaO x , and AlNiO x ), the peak 96 °C was assigned to the weak adsorption of CO 2 on the support surface by OH groups, indicated by the weak basicity. , For the Ca-based materials (Ni/AlCaO x , AlCaO x , CaNiO x , and CaO x ), peaks were detected when the temperature exceeded 500 °C, corresponding to the formation of bicarbonates or carbonates . This was attributed to bulk oxygen anion/oxygen vacancies, leading to the strong basicity. , The adsorbed O 2– sites associated with CO 2 desorption from 300 to 700 °C significantly enhanced the formation of monodentate carbonates and their subsequent hydrogenation to monodentate formates . For the AlNiO x sample, a peak at 200 °C was assigned to the medium-strength basic sites resulting from surface oxygen anions .…”

“…This was attributed to bulk oxygen anion/oxygen vacancies, leading to the strong basicity. , The adsorbed O 2– sites associated with CO 2 desorption from 300 to 700 °C significantly enhanced the formation of monodentate carbonates and their subsequent hydrogenation to monodentate formates . For the AlNiO x sample, a peak at 200 °C was assigned to the medium-strength basic sites resulting from surface oxygen anions . The peak at 200 °C is most likely relevant to the breakdown of a Ni-related new substance, which occurs at less than 300 °C.…”

“…51,52 For the Ca-based materials (Ni/AlCaO x , AlCaO x , CaNiO x , and CaO x ), peaks were detected when the temperature exceeded 500 °C, corresponding to the formation of bicarbonates or carbonates. 52 This was attributed to bulk oxygen anion/oxygen vacancies, 53 leading to the strong basicity. 54,55 The adsorbed O 2− sites associated with CO 2 desorption from 300 to 700 °C significantly enhanced the formation of monodentate carbonates and their subsequent hydrogenation to monodentate formates.…”

“…56 For the AlNiO x sample, a peak at 200 °C was assigned to the medium-strength basic sites resulting from surface oxygen anions. 53 The peak at 200 °C is most likely relevant to the breakdown of a Ni-related new substance, which occurs at less than 300 °C. However, no corresponding peaks were observed for the NiO x sample and other Ca-containing samples.…”

Ultrathin Nitrogen‐Doped Carbon Encapsulated Ni Nanoparticles for Highly Efficient Electrochemical CO2 Reduction and Aqueous Zn‐CO2 Batteries

“…The moderate strength is assigned to chemisorption involving surface anions, and the strong alkaline is chemisorption produced by the interaction of active sites. [ 21 ] Moreover, the higher desorption temperature represents the stronger chemical adsorption of CO 2 on the catalytic sites, and the different desorption peaks represent the different adsorption sites for the catalyst. The desorption peak of chemisorbed CO 2 on Ni@N‐C is mainly at a higher temperature of 355 °C, and Ni@C catalyst has three lower desorption peaks at 94 °C, 208 °C, and 311 °C, the desorption peak located at 94 °C can be attributed to the weak physical adsorption, while the desorption peaks at 208 °C and 311 °C are assigned to the strong CO 2 chemisorption.…”