Optimizing the Electronic Structure of Ordered Pt–Co–Ti Ternary Intermetallic Catalyst to Boost Acidic Oxygen Reduction

Abstract

Developing advanced electrocatalysts toward the sluggish oxygen reduction reaction (ORR) kinetics is critical to fuel cells but still an enormous challenge at present. Here, we demonstrate a highly active and durable Pt-based ternary catalyst, ordered Pt3Co0.6Ti0.4 intermetallic nanoparticles (∼3 nm) supported on ZIF-8-derived mesoporous carbon (Pt3Co0.6Ti0.4/DMC). The Pt3Co0.6Ti0.4/DMC catalyst exhibits faster ORR kinetics compared to Pt3Co/DMC and commercial Pt/C with minimal activity loss (20.1%) and only 5 mV decay in half-wave potential after 20,000 potential cycles. More importantly, its improved performances have also been proven in the H2/air PEM single cell test. The theoretical calculations reveal that the substitution of Ti for Co induces a strengthened ligand effect and optimizes the surface electronic structure of Pt3Co0.6Ti0.4, resulting in the significantly enhanced ORR activity. This work provides a reliable and promising approach for the development of efficient and robust Pt-based ternary intermetallic electrocatalysts for practical fuel cell applications.

Atomic order transition of TiNiPt nanoparticles supported on carbon nanotubes for the stable hydrogen evolution reaction

“…As a result, strong electron transfer occurs in O-Ti 50 Ni 30 Pt 20 /CNT; the electron density of Ni increases and that of Pt decreases. 36 The atomic ratios of Pt 0 /Pt 2+ and Ni 2+ /Ni 0 in O-Ti 50 Ni 30 Pt 20 /CNT are about 1.516 and 13.652 (calculated from the integrated areas of the corresponding peaks in Fig. 5b and c), respectively, while the atomic ratios of Pt 0 /Pt 2+ and Ni 2+ /Ni 0 in D-Ti 50 Ni 30 Pt 20 /CNT are about 1.083 and 37.324, 37 respectively.…”

Design principles for the synthesis of platinum–cobalt intermetallic nanoparticles for electrocatalytic applications

“…In this feature article, we coin the term ''half-intermetallic'' to describe a ternary or multimetallic system, in which one lattice site (i.e., Pt) is fully ordered, while the other lattices site is occupied by secondary metal atoms (i.e., non-Pt metals) that can be randomly distributed. [77][78][79] The amount of the incorporated metal is typically small (o10 at%). For example, tungsten (W) atom was reported to be incorporated into L1 0 -PtCo NPs to form a half-intermetallic of W 0.05 PtCo.…”

“…For example, the porosity of mesoporous carbon helps to control the particle size. 33,78,94 The synthesis procedures are generally similar to those of nonporous systems. Mesoporous carbon support is firstly obtained by the annealing of ZIF-8 or its derivatives.…”

“…The metal precursors are impregnated onto the mesoporous carbon, and the mixture is dried either by heat treatment or freeze drying. 78,94,95…”

Enhancement Mechanism of Pt/Pd-Based Catalysts for Oxygen Reduction Reaction

“…Most importantly, these elements have more obvious atomic radius differences and mismatched lattice constants with Pt/Pd, which may lead to more severe structural strains affecting the catalytic process. Zhao and co-workers demonstrated an efficient ternary catalyst consisting of Pt 3 Co 1−x Ti x supported on mesoporous carbon derived from ZIF-8 by an improved impregnation reduction method [ 39 ]. The electron regulation effect of Ti on Pt was investigated by changing the substitution ratio of Ti to Co.…”