1
|
Yang H, Zhang A, Bai Y, Chu M, Li H, Liu Y, Zhu P, Chen X, Deng C, Yuan X. One Stone Two Birds: Unlocking the Synergy between Amorphous Ni(OH) 2 and Pd Nanocrystals toward Ethanol and Formic Acid Oxidation. Inorg Chem 2022; 61:14419-14427. [PMID: 36037068 DOI: 10.1021/acs.inorgchem.2c02307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Even though extensive efforts have been devoted to mixing Pd nanocrystals with Ni(OH)2 for the enhanced synergy, it remains a great challenge to incorporate nanosized Ni(OH)2 species on the Pd electrode and reveal their synergy. Herein, we present spongelike Pd nanocrystals with the modification of amorphous Ni(OH)2 species. The catalyst configuration is first considered by compositing Pd with Ni(OH)2 species to optimize the Pd-Pd interatomic distance and then constructing a strongly coupled interface between Pd nanostructures and Ni(OH)2 species. For the ethanol oxidation reaction (EOR) and the formic acid oxidation reaction (FAOR), Pd-Ni(OH)2 composites exhibit an impressive mass activity of 4.98 and 2.65 A mgPd-1, respectively. Most impressively, there is no significant decrease in the EOR activity during five consecutive cycles (50 000 s). A series of CO-poisoning tests have proved that the enhanced EOR and FAOR performances involve synergy between Pd nanostructures and Ni(OH)2 species.
Collapse
Affiliation(s)
- Hu Yang
- School of Chemistry and Chemical Engineering, Nantong University, 9 Seyuan Road, Nantong 226019, China
| | - Aichuang Zhang
- School of Chemistry and Chemical Engineering, Nantong University, 9 Seyuan Road, Nantong 226019, China
| | - Yunfei Bai
- Space Power Technology State Key Laboratory, Shanghai Institute of Space Power-Sources, 2965 Dongchuan Road, Shanghai 200245, China
| | - Mingyu Chu
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, 199 Ren'ai Road, Suzhou 215123, China
| | - Han Li
- School of Chemistry and Chemical Engineering, Nantong University, 9 Seyuan Road, Nantong 226019, China
| | - Yuan Liu
- School of Chemistry and Chemical Engineering, Nantong University, 9 Seyuan Road, Nantong 226019, China
| | - Peng Zhu
- School of Chemistry and Chemical Engineering, Nantong University, 9 Seyuan Road, Nantong 226019, China
| | - Xiaolei Chen
- School of Chemistry and Chemical Engineering, Nantong University, 9 Seyuan Road, Nantong 226019, China
| | - Chengwei Deng
- Space Power Technology State Key Laboratory, Shanghai Institute of Space Power-Sources, 2965 Dongchuan Road, Shanghai 200245, China
| | - Xiaolei Yuan
- School of Chemistry and Chemical Engineering, Nantong University, 9 Seyuan Road, Nantong 226019, China
| |
Collapse
|
2
|
Structural Evolution and Magnetic Properties of Gd 2Hf 2O 7 Nanocrystals: Computational and Experimental Investigations. Molecules 2020; 25:molecules25204847. [PMID: 33096660 PMCID: PMC7587975 DOI: 10.3390/molecules25204847] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 10/14/2020] [Accepted: 10/16/2020] [Indexed: 11/17/2022] Open
Abstract
Structural evolution in functional materials is a physicochemical phenomenon, which is important from a fundamental study point of view and for its applications in magnetism, catalysis, and nuclear waste immobilization. In this study, we used x-ray diffraction and Raman spectroscopy to examine the Gd2Hf2O7 (GHO) pyrochlore, and we showed that it underwent a thermally induced crystalline phase evolution. Superconducting quantum interference device measurements were carried out on both the weakly ordered pyrochlore and the fully ordered phases. These measurements suggest a weak magnetism for both pyrochlore phases. Spin density calculations showed that the Gd3+ ion has a major contribution to the fully ordered pyrochlore magnetic behavior and its cation antisite. The origin of the Gd magnetism is due to the concomitant shift of its spin-up 4f orbital states above the Fermi energy and its spin-down states below the Fermi energy. This picture is in contrast to the familiar Stoner model used in magnetism. The ordered pyrochlore GHO is antiferromagnetic, whereas its antisite is ferromagnetic. The localization of the Gd-4f orbitals is also indicative of weak magnetism. Chemical bonding was analyzed via overlap population calculations: These analyses indicate that Hf-Gd and Gd-O covalent interactions are destabilizing, and thus, the stabilities of these bonds are due to ionic interactions. Our combined experimental and computational analyses on the technologically important pyrochlore materials provide a basic understanding of their structure, bonding properties, and magnetic behaviors.
Collapse
|
3
|
Wang B, Gao M, Uosaki K, Taketsugu T. A quantum chemical study of substituent effects on CN bonds in aryl isocyanide molecules adsorbed on the Pt surface. Phys Chem Chem Phys 2020; 22:12200-12208. [PMID: 32427247 DOI: 10.1039/d0cp00760a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
A periodicity implemented scheme of natural bond orbital (NBO) theory and normal mode analysis has been employed to investigate the tendency of the chemical bond strength of aryl isocyanide molecules with different para-substituted groups adsorbed on the Pt(111) surface. The NC bond order shows a clear correspondence with the NC stretching frequency; both of them exhibit a "volcano-like" profile as a function of the Hammett constant of the para-substituted groups for isolated molecules. When a molecule is adsorbed on the Pt(111) surface, the NC stretching frequency variations are determined by the resultant effect of σ donation and π back-donation between the molecule and the surface. The present comprehensive and systematic computations clarify the electron donating and withdrawing effects of the substituted groups on the interaction between the aryl isocyanide molecule and the transition metal substrate.
Collapse
Affiliation(s)
- Ben Wang
- Graduate School of Chemical Sciences and Engineering, Hokkaido University, Sapporo 060-0810, Japan
| | | | | | | |
Collapse
|