Coherence of interface between Pd and local tetrahedral symmetric Ni oxide intensifies local synergetic collaboration in CO2 thermal methanation

Che Yan^1*, Chia-Hsin Wang², Moore Lin³, Dinesh Bhalothia¹, Shou-Shiun Yang¹, Gang-Jei Fan³, Jia-Lin Wang³, Ting-Shan Chan², Yao-lin Wang⁴, Xin Tu⁴, Sheng Dai⁵, Kuan-Wen Wang⁶, Jr-Hau He⁷, Tsan-Yao Chen^1,8,9

¹Department of Engineering and System Science, National Tsing Hua University, Hsinchu, Taiwan
²National Synchrotron Radiation Research Center, National Synchrotron Radiation Research Center, Taiwan
³Department of Chemistry, National Central University, Taoyuan, Taiwan
⁴Department of Electrical Engineering & Electronics, University of Liverpool, Liverpool, UK
⁵School ofChemistry & Molecular Engineering, East China University of Science and Technology, Shanghai, China
⁶Institute ofMaterials Science and Engineering, National Central University, Taoyuan, Taiwan
⁷Department ofMaterials Science and Engineering, City University ofHong Kong, Hong Kong
⁸Institute ofNuclear Engineering and Science, National Tsing Hua University, Hsinchu, Taiwan
⁹Hierarchical Green-Energy Materials (Hi-GEM) Research Centre, National Cheng Kung University, Tainan, Taiwan

* Presenter:Che Yan, email:st90437@gmail.com

Synergetic collaboration is a vital mechanism in the nanometer regime for CO2 reduction reaction. Different molecule adsorption affinities (e.g. Hads, COads…) enable the intermediate reaction steps, such as dissociation of CO2, H2 splitting, and CO hydrogenation, to initiate simultaneously. In this study, the good coherence of the interface between metallic Pd and Ni oxide refers to a powerful synergetic collaboration. By cross-referencing the results of the physical structure inspections, in situ ambient pressure X-ray photoelectron spectroscopy, and gas chromatography-mass spectrometer analysis, the high concentration of Pd ions (denoted as NiOTPd30-T) introduces the galvanic replacement effect and builds a mismatched interface on Ni oxide, instead, the low concentration one (denoted as NiOTPd15-T) possesses an almost coherent interface. Indeed, the NiOTPd15-T nanocatalyst (NC) demonstrates both optimum production yields of 3629.5 μmol g-1catalyst of CO and 1905.1 μmol g-1catalyst of CH4 as compared to that of NiOTPd30-T at 573 K. Although the average area of the interface in one NiOTPd30-T nanoparticle is larger than that of NiOTPd15-T, the mismatched interface and the intermixing between the Pd atoms and Ni atoms weaken the local synergetic collaboration. Most importantly, this study exhibits the coherence of the interface between metal and metal oxide determines the effectiveness in the synergetic collaboration.

Keywords: Synergetic collaboration, CO2 reduction reaction, Nanocatalyst, wet chemical reduction