Dynamic oxygen migration and reaction over ceria-supported nickel oxides in chemical looping partial oxidation of methane

Functional CeOx Stabilized Metallic Ni Catalyst Supported on Boron Nitride for Durable Partial Oxidation of Methane to Syngas at High Temperature

“…44 In contrast, 4Ni/7.5Ce/BN-fresh presents a higher reduction peak at 579 °C, which could be ascribed to the reduction of the NiO species and the reduction of surface cerium species. 49,50 The peak at 237 °C is assigned to the Ni−O−Ce interfacial site, which is readily removed by hydrogen. 45 The lower reduction temperatures suggested the enhanced H-spillover effect over the metallic Ni site, improving the reducibility and lowering the reduction temperature under a H 2 atmosphere, which is consistent with the catalytic performance.…”

Advances and Challenges in Oxygen Carriers for Chemical Looping Partial Oxidation of Methane

“…They also found that CuO/cordierite and NiO/cordierite have high conversion rates for both CO 2 and CH 4 in each cycle, with high selectivity for CO Regarding the CH 4 conversion, the two fractions maintained a high conversion in the reaction, as well as a strong cyclic stability [48]. Liu et al described the dynamic migration of the oxygen species on cerium oxide-based NiO OCs in CLPOM, and they found that the content of oxygen species was directly correlated and linearly related to the rate of CO generation; meanwhile, the consumed Ni-O-Ce oxygen species were supplemented by the lattice oxygen in CeO 2 , as shown in Figure 3b [23]. Li et al prepared xNiO/(CeO 2 -MgO) OC and demonstrated that the activity of CH 4 and CO 2 conversion increased significantly with the addition of NiO, and the addition of 10wt% to the NiO increased the CH 4 conversion from 15.62% to 59.64% at 800 • C. In addition, the stability was also greatly improved due to the formation of the CeO 2 -NiO and NiO-MgO double solid solutions.…”

“…Liu et al synthesized 5NiO/(xCeO 2 -Al 2 O 3 ) oxygen carriers by two-step impregnation.The stable and highly active oxygen carrier was synthesized to minimize the formation of NiAl 2 O 4 and the Ni 2+ doping into the CeO 2 lattice. The active Ni-O-Ce oxygen species can be devoted to partial oxidation performance, and the deactivation was found to be negligible for 5NiO/(40CeO 2 -Al 2 O 3 ) over 20 cycles[23]. For stable monoatomic deposition, Carrillo et al employed the exsolution technique to achieve consistent monoatomic deposition, thus resulting in evenly distributed Ru nanoparticles that were firmly attached to the cerium oxide framework.…”

Chemical looping methanol oxidation using supported vanadium phosphorous oxide carriers for formaldehyde production

“…To achieve stability of the oxygen carrier, its active components are oen dispersed on a support. [42][43][44][45][46] Our preliminary analysis and literature indicate that SiO 2 can serve as a support for VOPO 4 as it does not react with either vanadium or phosphorous and has already been utilized as a carrier support for various applications. 31,[47][48][49][50] The CLMO process using the VPO carrier can be broken down into two steps.…”