In Silico High-Throughput Screening of Ag-Based Electrocatalysts for Anion-Exchange Membrane Fuel Cells

Abstract

The alkaline environment in anion-exchange membrane fuel cells allows the use of Pt-free electrocatalysts, thus reducing the system cost. We performed a theoretical high-throughput study of various low-cost Ag-based oxygen reduction reaction anode electrocatalysts and assessed their catalytic performance using density functional theory. From the Materials Project database, a total of 106 binary Ag alloys were investigated by estimating their heat of formation, dissolution potential, and overpotential on low-index surfaces. We confirmed that EuAg5, BaAg5, and SrAg5 have higher catalytic activities and durabilities than pure Ag. By following the chemical trend of the results, we further proposed LaAg5 and PrAg5, which were not included in the database, as promising candidates. All candidates are in the space group P6/mmm and contain alkaline earth metal or lanthanide elements.

Formulating electronic descriptors to rationally design graphene-supported single-atom catalysts for oxygen electrocatalysis

“…To conrm the catalytic activity of the Cu-N-C, we drew a 2-D activity plot that showed the overpotential values for DE O and DE OH with the Cu-N-C point using eqn ( 5)-( 9) and the scaling relationship between DE OH and DE OOH . 5,32,33 The result is shown in Fig. S6.…”

“…Therefore, several approaches have been proposed to reduce the usage of precious PGMs while maintaining high catalytic performance. [5][6][7][8][9][10][11][12] Recently, graphenesupported single-atom catalysts (G-SACs) have been demonstrated to be one of the best of these strategies because G-SACs not only decrease the amount of loaded precious metal but also improve the mass activity by maximizing the atomic efficiency with high product selectivity. 2,3,13,14 However, G-SACs always face stability issues owing to the high chemical potential of single atoms, particularly agglomeration and dissolution.…”

A Hybrid of the Fe4N–Fe Heterojunction Supported on N-Doped Carbon Nanobelts and Ketjen Black Carbon as a Robust High-Performance Electrocatalyst

“…The efficiency and performance of fuel cells have been being deeply plagued by the inherently sluggish kinetics of oxygen electrocatalysis, especially the cathodic oxygen reduction reaction (ORR). − To date, exorbitantly priced noble-metal-based materials, especially Pt-based materials (PBMs in short), have been deemed the most powerful electrocatalysts for expediting the ORR by dint of lowering its energy barrier. , However, except for the exorbitant price, the undesirable durability and poor methanol tolerance of PBMs also frustrate the spread of the application of fuel cells. − Hence, exploring highly efficient and cost-competitive PBM-free electrocatalysts without compromising the activity is highly desirable and urgently needed. − Among the PBM-free electrocatalysts, Fe-based materials represented by Fe–N–C electrocatalysts hold broad application prospects sparked by their high ORR activities and abundance in the Earth’s crust. − In fewer than 10 years, Fe-based single-atom catalysts (FSACs) have attracted an enormous amount of attention in ORR because of their 100% theoretical atom-utilization efficiency and excellent catalytic performance. − Unfortunately, most methods for preparing FSACs are complicated and need to be manipulated with elaboration, which frequently involve the deposition of an Fe-containing precursor on a support, succeeded by pyrolysis alongside reduction under a suitable gaseous environment . Recently, presynthesized metal–organic frameworks (MOFs) as precursors have demonstrated a superior ability to synthesize highly porous FSACs by direct pyrolysis, commonly accompanied by ammonia activation. , In these strategies, acid leaching procedures are usually involved to etch non-single-atom Fe-based species such as nanoparticles, which also corrodes the catalytic sites .…”