A superior titanium glycolate-based catalyst for thermo- and photocatalytic formic acid dehydrogenation (FADH) is synthesized for hydrogen evolution. Carbon-decorated mesoporous anatase TiO2 nanospheres (CTNSs) are obtained by the hydrolysis of titanium glycolate nanospheres (TGNSs). The selection of TGNSs as the precursor of the support allows varying the extent of carbon decoration, crystallinity, mean crystallite size, Ti(III)/Ti(IV) ratio, and oxygen vacancy of TiO2-based catalyst by controlling the hydrolysis time. A series of catalysts are obtained by immobilization of ultrafine PdAu nanoalloy onto amine-functionalized CTNSs with different crystalline properties and carbon contents. The nanocatalyst obtained using CTNSs with the lowest crystallinity (78.4%), smallest crystallite size (3.98 nm), and densely carbon-decorated anatase phase with a high oxygen vacancy (40.65%) and high Ti(III)/Ti(IIV) ratio (0.409) with a band gap energy of 1.255 eV (PdAu@ACTNSs-1) provides an exceptional TOF of 20,924 h–1 with 100% H2 selectivity in catalytic FADH at 60 °C. A TOF of 34,877 h–1 was obtained at 80 °C. TOFs up to 1507 h–1 are observed in visible-light-driven photocatalytic FADH at 25 °C via 1O2, •OH radicals, and electron holes. PdAu@ACTNS-1 exhibits high stability over thermo-/photocatalytic FADHs. The synthetic route presents an innovative strategy for developing new high-performance catalysts for organic reactions.
Hamdan et al. (Tue,) studied this question.