One-pot synthesis of lattice-strained AuPt spine-like nanotubes for high-efficiency ethanol electrooxidation

We report a facile one-pot synthesis of AuPt spine-like nanotubes (AuPt SNTs) with abundant defective sites and lattice strain surfaces, which synergistically enhance EOR performance. The synthesis involves controlled co-reduction of Au and Pt precursors in the presence of octadecyltrimethylammonium chloride as a structure-directing agent, followed by ascorbic acid-mediated growth at 3-5 °C regulated by a cryogenic coolant circulation system. The unique spine-like nanotube architecture, coupled with defect-rich surfaces and lattice strain, provides optimized electronic structures, enhanced active site exposure, and improved reactant diffusion kinetics. Electrochemical tests demonstrate that AuPt SNTs exhibit a mass activity of 2.9 A mg_Pt^-1 and a specific activity of 101.2 mA cm^-2 for the EOR, which are 7.3 times and 48.2 times higher than those of commercial Pt/C and retain superior specific activity after chronoamperometry for a 3000 s duration. In situ SERS analysis confirmed that both the C1 and C2 pathway and the enhanced EOR activity can be attributed to the synergy between the stepped sites and expansion of lattice spacing, which is further supported by DFT calculations that the C-C bond cleavage is indeed enhanced on the surface of stepped AuPt SNTs. This work highlights the importance of defect and strain engineering in designing advanced nanostructured catalysts.