which is also considered a biorenew able energy carrier. However, the anodic ethanol oxidation reaction (EOR) is a complicated and kinetically sluggish process, involving the transfer of multiple electrons and various reaction intermediates and products. Typically, the C2-pathway dominates the EOR in both acidic and alkaline electrolytes, resulting in the formation of acetic acid or acetate by delivering four electrons, and acetaldehyde by delivering two electrons, respectively. The C1-pathway, which involves complete oxidation and the transfer of 12 electrons generating CO 2 or carbonate, is preferred to the C2-pathway, aiming for maximum DEFCs efficiency. [1][2][3][4][5] Specially, highly efficient catalysts have been developed by engineering Pt-based nanocrystals, and the C1-pathway selectivity has been promoted by Rh-based catalysts. [6][7][8][9] In designing electrochemical surfaces toward maximum performance, modifying the electronic structure and strain of catalytic surfaces are considered state-of-the-art strategies, which can for instance be achieved by introducing metals with different intrinsic reactivities and constructing core-shell nanostructures, respectively. [10][11][12][13][14][15] Combining these approaches in a rational manner would be a promising way to substantially improve the EOR, yet the underlying knowledge about their contributions is largely lacking. [10][11][12][13][14][15][16][17][18] Therefore, it is highly desirable to employ tailored nanostructures to resolve these important issues and contribute to the practical deployment of DEFCs by identifying versatile EOR electrocatalysts possessing high atom utilization of noble metals, high mass-normalized activity at low overpotentials, high C1-pathway selectivity, long-term durability, and superior anti-poisoning ability. [1] To maximize atom utilization, single-atom catalysts (SACs) have emerged as one of the most promising frontiers in materials chemistry. [19][20][21] Using specific support materials such as reducible metal oxides, activated carbons, and anisotropic materials such as MoS 2 , single atoms of catalytically metals can be stabilized, which exhibit intriguing physicochemical properties compared with their counterpart clusters and nanoparticles. [22][23][24] Typically, high-performance EOR catalysts should facilitate multiple dehydrogenation and oxidation steps as well as CC bond cleavage reactions. All these reactions typically require ensembles of surface metal atoms, implying that thisThe rational design and control of electrocatalysts at single-atomic sites could enable unprecedented atomic utilization and catalytic properties, yet it remains challenging in multimetallic alloys. Herein, the first example of isolated Rh atoms on ordered PtBi nanoplates (PtBi-Rh 1 ) by atomic galvanic replacement, and their subsequent transformation into a tensile-strained Pt-Rh single-atom alloy (PtBi@PtRh 1 ) via electrochemical dealloying are presented. Benefiting from the Rh 1 -tailored Pt (110) surface with tensile strain, the PtBi@...
The coordinated configuration of atomic platinum (Pt) has always been identified as an active site with high intrinsic activity for hydrogen evolution reaction (HER). Herein, we purposely synthesize single vacancies in a carbon matrix (defective graphene) that can trap atomic Pt to form the Pt–C3 configuration, which gives exceptionally high reactivity for HER in both acidic and alkaline solutions. The intrinsic activity of Pt–C3 site is valued with a turnover frequency (TOF) of 26.41 s–1 and mass activity of 26.05 A g–1 at 100 mV, respectively, which are both nearly 18 times higher than those of commercial 20 wt % Pt/C. It is revealed that the optimal coordination Pt–C3 has a stronger electron-capture ability and lower Gibbs free energy difference (ΔG), resulting in promoting the reduction of adsorbed H+ and the acceleration of H2 desorption, thus exhibiting the extraordinary HER activity. This work provides a new insight on the unique coordinated configuration of dispersive atomic Pt in defective C matrix for superior HER performance.
Platinum is the most effective metal for a wide range of catalysis reactions, but it fails in the formic acid electrooxidation test and suffers from severe carbon monoxide poisoning. Developing highly active and stable catalysts that are capable of oxidizing HCOOH directly into CO2 remains challenging for commercialization of direct liquid fuel cells. A new class of PtSnBi intermetallic nanoplates is synthesized to boost formic acid oxidation, which greatly outperforms binary PtSn and PtBi intermetallic, benefiting from the synergism of chosen three metals. In particular, the best catalyst, atomically ordered Pt45Sn25Bi30 nanoplates, exhibits an ultrahigh mass activity of 4394 mA mg−1 Pt and preserves 78% of the initial activity after 4000 potential cycles, which make it a state‐of‐the‐art catalyst toward formic acid oxidation. Density functional theory calculations reveal that the electronic and geometric effects in PtSnBi intermetallic nanoplates help suppress CO* formation and optimize dehydrogenation steps.
In situ synthesized oxygen vacancy-enriched MoO3−x nanobelts realized excellent electrochemical performance as asymmetric supercapacitors at room/low temperature.
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