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 C -Pt-Cl species in Pt-GDY1 and four-coordinated C -Pt-Cl 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.

The design and synthesis of efficient metal‐free photoelectrocatalysts for water splitting are of great significance, as nonmetal elements are generally earth abundant and environment friendly. As a typical metal‐free semiconductor, g‐C3N4 has received much attention in the field of photocatalytic water splitting. However, the poor photoinduced hole mobility of g‐C3N4 restrains its catalytic performance. Herein, for the first time, graphdiyne (GDY) is used to interact with g‐C3N4 to construct a metal‐free 2D/2D heterojunction of g‐C3N4/GDY as an efficient photoelectrocatalyst for water splitting. The g‐C3N4/GDY photocathode exhibits enhanced photocarriers separation due to excellent hole transfer nature of graphdiyne and the structure of 2D/2D heterojunction of g‐C3N4/GDY, realizing a sevenfold increase in electron life time (610 μs) compared to that of g‐C3N4 (88 μs), and a threefold increase in photocurrent density (−98 μA cm−2) compared to that of g‐C3N4 photocathode (−32 μA cm−2) at a potential of 0 V versus normal hydrogen electrode (NHE) in neutral aqueous solution. The photoelectrocatalytic performance can be further improved by fabricating Pt@g‐C3N4/GDY, which displays an photocurrent of −133 μA cm−2 at a potential of 0 V versus NHE in neutral aqueous solution. This work provides a new strategy for the design of efficient metal‐free photoelectrocatalysts for water splitting.

TwoP ts ingle-atom catalysts (SACs) of Pt-GDY1 and Pt-GDY2 were prepared on graphdiyne (GDY)supports. The isolated Pt atoms are dispersed on GDYt hrough the coordination interactions between Pt atoms and alkynyl C atoms in GDY, with the formation of five-coordinated C 1 -Pt-Cl 4 species in Pt-GDY1 and four-coordinated C 2 -Pt-Cl 2 species in Pt-GDY2. Pt-GDY2 shows exceptionally high catalytic activity for the hydrogen evolution reaction (HER), with am ass 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.P t-GDY2 possesses higher total unoccupied density of states of Pt 5d orbital and close to zero value of Gibbsfree energy of the hydrogen adsorption (j DG Pt H* j)atthe Pt active sites,w hich are responsible for its excellent catalytic performance.T his work can help better understand the structure-catalytic activity relationship in Pt SACs.

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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...