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Developing highly active catalysts for photo/electrocatalytic water splitting is an attractive strategy to produce H2 as a renewable energy source. In this study, a new nickel boron oxide/graphdiyne (NiBi/GDY) hybrid catalyst was prepared by a facile synthetic approach. Benefitting from the strong electron donating ability of graphdiyne, NiBi/GDY showed an optimized electronic structure containing lower valence nickel atoms and demonstrated improved catalytic performance. As expected, NiBi/GDY displayed a high photocatalytic H2 evolution rate of 4.54 mmol g−1 h−1, 2.9 and 4.5 times higher than those of NiBi/graphene and NiBi, respectively. NiBi/GDY also displayed outstanding electrocatalytic H2 evolution activity in 1.0 M KOH solution, with a current density of 400 mA/cm2 at an overpotential of 478.0 mV, which is lower than that of commercial Pt/C (505.3 mV@400 mA/cm2). This work demonstrates that GDY is an ideal support for the development of highly active catalysts for photo/electrocatalytic H2 evolution.

The development of efficient heterogeneous catalysts for alkyne hydrogenation with high activity and selectivity is highly desirable and yet remains a great challenge. Herein, a Pd single-atom catalyst (Pds–GDY) is prepared using graphdiyne as support, and used in the semihydrogenation of alkynes. As a proof of concept, the Pds–GDY exhibits a high activity for the semihydrogenation of phenylacetylene under mild reaction conditions, with a TOF of 6290 h−1, and a selectivity of 99.3% at 100% conversion, both much higher than those of the counterparts comprising Pd nanoparticles (NPs), namely, PdNP1–GDY (with 2 nm Pd NPs) and PdNP2–GDY (with 12 nm Pd NPs). In addition, after the full conversion of phenylacetylene, Pds–GDY could still maintain a selectivity as high as 98.9% towards styrene, with almost no phenylethane produced even with a prolonged reaction time; in contrast, for PdNP1–GDY and PdNP2–GDY, within the same reaction time, the selectivity decreases dramatically to 66.6% and 8.5%, respectively. Infrared spectroscopy reveals that Pds–GDY features the weakest adsorption to styrene, which is responsible for its high performance. This work provides an effective strategy to rationally design Pd catalysts for semihydrogenation of alkynes to alkenes with desirable activity and selectivity.

A visible-light-response, efficient and robust photo-catalyst for CO2 reduction is highly desirable. Herein, we demonstrate that single titanium-oxide species implanted in two-dimensional (2D) graphitic carbon nitride (g-C3N4) matrix (2D TiO-CN) can efficiently photo-catalyze the reduction of CO2 to CO under the irradiation of visible light. The synergistic interaction between single titanium oxide species and g-C3N4 in 2D TiO-CN not only enhances the separation of photo-excited charges, but also results in visible light response of single titanium-oxide species, realizing high activity of CO2 photo-reduction with extremely high CO generation rate of 283.9 μmol·h−1·g−1, 5.7, 6.8 and 292.2 times larger than those of TiO2/CN hybrid material, CN and commercial TiO2, respectively. Time-resolved fluorescence and electron spin resonance spectroscopy revealed the catalytic mechanism of the fabricated 2D TiO-CN photocatalysts for CO2 reduction.

Two Pt single-atom catalysts (SACs) of Pt-GDY1 and Pt-GDY2 were prepared on graphdiyne (GDY)supports. The isolated Pt atoms are dispersed on GDY through the coordination interactions between Pt atoms and alkynyl C atoms in GDY, with the formation of five-coordinated C1 -Pt-Cl4 species in Pt-GDY1 and four-coordinated C2 -Pt-Cl2 species in Pt-GDY2. Pt-GDY2 shows exceptionally high catalytic activity for the hydrogen evolution reaction (HER), with a mass activity up to 3.3 and 26.9 times more active than Pt-GDY1 and the state-of-the-art commercial Pt/C catalysts, respectively. Pt-GDY2 possesses higher total unoccupied density of states of Pt 5d orbital and close to zero value of Gibbs free energy of the hydrogen adsorption (|ΔGPtH* |) at the Pt active sites, which are responsible for its excellent catalytic performance. This work can help better understand the structure-catalytic activity relationship in Pt SACs.