期刊
CHEMICAL ENGINEERING JOURNAL
卷 425, 期 -, 页码 -出版社
ELSEVIER SCIENCE SA
DOI: 10.1016/j.cej.2021.131642
关键词
Electrocatalysts; Metal phosphide; Heteroatom doping; Oxygen evolution reaction; DFT calculation
资金
- National Natural Science Foundation of China [21705106]
- Program for Professor of Special Appointment (Eastern Scholar) at Shanghai Institutions of Higher Learning [TP2016023]
- Shanghai Natural Science Foundation [18ZR1415400]
- Shanghai Sailing Program [20YF1413000]
Mn-doped cobalt phosphide porous nanosheets were designed for efficient oxygen evolution reaction, showing impressive catalytic performance under alkaline conditions. In-situ transformation to Mn-CoOOH provides additional active sites for improved activity. Density functional theory calculations demonstrate that Mn doping enhances gap states near active O sites, facilitating deprotonation reactions and reducing energy barriers for rate-determining steps.
Transition metal phosphides (TMP) show great potential to alternative noble metal based electrocatalysts for oxygen evolution reaction (OER) electrolysis but the still unsatisfactory catalytic activity hinders its practical application. Therefore, it is of much significance to rationally design TMP electrocatalysts for achieving high-efficiency OER. Here, we design Mn-doped cobalt phosphide (Mn-CoP) porous nanosheets for highly active OER through the in-situ metal acetate hydroxide transformation and subsequent phosphidation treatment. Benefiting from synergistic effects of the porous structure, high density of active sites and improved charge-transfer capability, the optimized Mn-CoP serving as a pre-catalyst shows an impressive alkaline OER performance with a low overpotential of 288 mV at the current density of 10 mA cm(-2) and high stability. Post-electrolysis characterizations show the conversion from Mn-CoP to vertical Mn-CoOOH hexagonal nanosheets during OER, in which the transformed Mn-CoOOH not only provide extra active sites, but serve as the highly active species. Density functional theory (DFT) calculations reveal that Mn doping can increase the gap states near the Fermi level of active O sites, endowing facilitated deprotonation of OH* to O* and reducing the energy barrier of rate-determining step. This protocol provides a novel insight for the construction of highly efficient TMP water oxidation electrocatalysts.
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