Generalized synthetic strategies for nanostructures with well-defined physical dimensions and broad-range chemical compositions is at the frontier of advanced nanomaterials design, functionalization, and application. Metal phosphide nanostructures have attracted much attention due to their unique magnetic, semiconducting, mechanical, and catalytic properties. Meanwhile, one-dimensional (1-D) metal phosphide nanostructures are of particular interests, as the strong anisotropic effect makes their physicochemical properties and functionalization potentials tunable. Organic phase colloidal synthesis that metal-phosphine complexes directly decompose is well established for monometallic phosphide nanorods and nanowires. However, the same method cannot be applied to 1-D multimetallic nanomaterials. Our lab managed to achieve a composition-programmable synthesis of multimetallic phosphide CoMPx nanorods wherein M can be controlled to be Fe, Ni, Mn, Cu, and their binary combinations. The conventional method of co-decomposition of different metal-organic complexes leads to uncontrollable morphology. To overcome this obstacle, we first obtain Co2P/MPx core/shell NRs through seed-mediated growth and subsequently convert them into CoMPx solid-solution NRs through thermal post-treatment. The resultant CoMPx with uniform 1-D structure provides us a platform to unambiguously screen the M synergistic effects in improving the electrocatalytic activity, as exemplified by the oxygen evolution reaction (OER). Supported on CNT, the resultant CoMPx NRs show M composition and concentration-dependent electrocatalytic properties for the OER, with the best activity being achieved on Co1.33Fe0.67Px. The 1-D shape/structure consistency and programmable composition make it possible to refine the composition-property relationship, especially for catalysis, while excluding the impact of size/shape/structural parameters. This new approach mediated by core/shell nanostructure formation and conversion can be extended to other multi-component nanocrystal systems (metal alloy, mixed oxide and chalcogenide, etc.) for diverse applications.

Programmable synthesis of multimetallic phosphide nanorods mediated by core/shell structure formation and conversion

ACS Spring Meeting 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.