Gold-Copper Aerogels with Intriguing Surface Electronic Modulation as Highly Active and Stable Electrocatalysts for Oxygen Reduction and Borohydride Oxidation

We, for the first time, report the successful synthesis of self-assembled AuCu aerogels by a one-pot kinetically controlled approach. A startling electronic modulation effect of Cu on Au was observed across the entire alloy composition range, for which the optimal upshift of the d-band center for the highest activities was 0.24 eV. Owing to the combination of a nanoporous architecture and a robust electronic effect, the Au52 Cu48 aerogels exhibited better catalytic performance for the oxygen reduction reaction (ORR) and the direct borohydride oxidation reaction (BOR) than commercial Pt/C catalysts. The specific and mass ORR activities were 4.5 and 6.3 times higher, respectively, on the Au52 Cu48 aerogels than on Pt/C with negligible activity decay even after 10 000 cycles and a duration of 40 000 s. For the BOR, the Au52 Cu48 aerogels also exhibited far better selectivity and activity than Pt/C. The new AuCu aerogels show great potential as a promising alternative for Pt-based catalysts in fuel cells.