Single‐Atom Pt Loaded on MOF‐Derived Porous TiO2 with Maxim‐ized Pt Atom Utilization for Selective Hydrogenation of Halonitro‐benzene

Abstract The location control of single atoms relative to supports is challenging for single‐atom catalysts, leading to a large proportion of inaccessible single atoms buried under supports. Herein, a “sequential thermal transition” strategy is developed to afford single‐atom Pt preferentially dispersed on the outer surface of TiO 2 . Specifically, a Ti‐MOF confining Pt nanoparticles is converted to Pt NPs and TiO 2 composite coated by carbon (Pt NPs &TiO 2 @C‐800) at 800 °C in N 2 . Subsequent thermal‐driven atomization of Pt NPs at 600 °C in air produce single‐atom Pt decorated TiO 2 (Pt 1 /TiO 2 ‐600). The resulting Pt 1 /TiO 2 ‐600 exhibits superior p ‐chloroaniline ( p ‐CAN) selectivity (99 %) to Pt NPs /TiO 2 ‐400 (45 %) and much better activity than Pt 1 @TiO 2 ‐600 with randomly dispersed Pt 1 both outside and inside TiO 2 in the hydrogenation of p ‐chloronitrobenzene ( p ‐CNB). Mechanism investigations reveal that Pt 1 /TiO 2 ‐600 achieves 100 % accessibility of Pt 1 and preferably adsorbs the –NO 2 group of p ‐CNB while weakly adsorbs –Cl group of p ‐CNB and p ‐CAN, promoting catalytic activity and selectivity.