A modified Galvani substitution protocol is proposed to fabricate serial Pt|Cu nanocrystals for hydrolyzing ammonia borane to generate H2 gas. The as‐fabricated Pt|Cu spheroidal nanocrystals with mean size of 75 nm hold porously hierarchical waxberry‐shaped appearance, with more subtle Pt grain cladding on Cu nanospheres to build the nanocrystal cluster frameworks. The lower Pt/Cu molar ratios result in the formation of a razor‐thin sublayer of Pt‐Cu alloy at the bimetallic interface; for the higher Pt/Cu molar ratios, no alloy phase forms, also without formation of probable oxides. The synergic effect contributes to the electron enrichment around Pt, helping to furnish more active sites. The catalytic ability increases with rising of Pt/Cu molar ratios; the Pt|Cu‐0.75 unfolds the abnormality even overtopping Pt NPs, with a turnover frequency value of 78.36 mol (H2)·min–1·(mol Pt)–1 and apparent activation energy of 32.89 kJ·mol–1. The catalytic hydrolytic reaction at the lower temperatures (298, 303 K) is identified as a first‐order reaction, while it belongs to second‐order reaction under the higher temperatures (308, 313, 318 K). The Pt|Cu‐0.75 nanocrystals express satisfactory stability with only 14% loss of the catalytic activity after 5‐time services, and excellent catalytic selectivity with no deleterious gas detected.

Titanium dioxide–titanium nitride composite (TiO2–TiN) nanoparticles (NPs) were used as a support to load nickel nano particles for the dehydrogenation of ammonia borane (AB) which is a new method. The composite support was fabricated via a simple ultrasonic mixing route, followed by the in situ loading of Ni NPs using a liquid-phase reduction reaction method where sodium borohydride was adopted as a reducing agent. The synthesized samples were characterized by X-ray diffraction spectra (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and Ultra Violet-Visible (UV–vis) analyses. The characterization results show that the Ni NPs uniformly dispersed on the support and existed in both zero and oxidized states. Compared with bare TiO2, Ni loading on TiO2–TiN exhibited a higher catalytic activity toward dehydrogenation of AB both under dark and under sunlight irradiation. Ni/10%TiN–TiO2 showed a hydrogen evolution rate with a turnover frequency (TOF) of 8.01 molH2 ·min–1·molcat –1 at 25 °C under sunlight. The loading of Ni NPs lowered the band gap energy of TiO2, resulting in the enhanced absorption of sunlight. The addition of TiN that acts as electron scavengers improved the separation efficiency of electron–hole pairs. Titanium dioxide–titanium nitride composites play an important role in improving the catalytic dehydrogenation of AB by nickel-based catalysts.

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A flexible and mild fabricating protocol, i.e., stepwise reduction and in situ loading route, is proposed to modulate ordered growing and dispersive depositing of Pt@Cu bimetal layered nanostructure on titanium dioxide nanotubes (TiO2‐NTs) via reasonably regulating addition sequence and dosage for the reactants and additives. Comprehensive characterizations demonstrate that most of the Cu core‐Pt shell nanocrystals with a mean size of 10 nm evenly disperse on the surface of TiO2‐NTs, and a small number of nanocrystals permeate into the nanotubes. In comparison to TiO2‐NTs, the specific surface area declines after loading bimetals, with the pore size distribution shifting from micropores to mesopores. The catalytic activity of the Pt@Cu(x)/TiO2 for hydrolytic hydrogen evolution presents an increasing tendency as the bimetal loadings rise, each surpassing that of the bare bimetal nanocrystals. The H2 generating rate gradually rises with temperature increment. The AB hydrolysis catalyzed by Pt@Cu(9%)/TiO2 at the given temperatures (293–313 K) is affirmed as a first‐order reaction, with apparent activation energy of 28.43 kJ mol−1 and TOF value of 107.27 min−1. The catalyst Pt@Cu(9%)/TiO2 unfolds exceptionally high stability, remaining 91% initial catalytic activity after five cycling use.

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