Developing stable and efficient photocatalysts for H production under visible light is still a big challenge. In this work, a novel covalent organic polymer (COP)-based photocatalyst with trace ending groups was prepared by the efficient irreversible kinetic coupling reaction, i.e., nickel(0)-catalyzed Yamamoto-type Ullmann cross-coupling, using pyrene as electron donor and countpart, e.g., phenanthrolene, benzene, pyrazine, as electron acceptor. The newly developed optimal photocatalyst (termed as COP-TP) has a 14-fold improvement in the H evolution rate from 3 to 42 μmol h under visible light compared with the sample without donor-acceptor structure. Moreover, COP-TP also performs excellent photocatalytic activity under different water quality (deionized water, municipal water, commercial mineral water, and simulated seawater (NaCl 3 wt %)). Significantly, ignored decrease in H evolution can be observed after 20 hours cycling H production, and the performance is only reduced by about 7% even after discontinuous cycles of photocatalysis and storage for a month. The donor-acceptor units with trace ending groups contribute to suppress electron-holes recombination kinetics and the N coordination sites in electron-acceptors conduce to anchor Pt (as the cocatalyst) onto the surface of photocatalyst, both of which are conducive to the outstanding photocatalytic activity and stability. Accordingly, this work can provide guidance to design a stable and efficient photocatalyst by copolymerization for visible-light-driven H production.

Organic photocatalysts are widely used to mimic artificial photosynthesis for sustainable solar-driven hydrogen production from water splitting. However, few photocatalytic H 2 production is reported using seawater, which is a significantly important parameter for practical application, and most organic photocatalysts employed precious and scarce Pt as a cocatalyst. Herein, we report an organic hybridized photocatalyst (termed COP-TF@CNi 2 P), carbon-encapsulated nickel phosphide, as a cocatalyst loaded on a fully conjugated organic polymer, which is applied for stable and efficient H 2 generation from seawater splitting. Both experiments and theory calculations suggest that the carbon layers covered around nickel phosphide not only can strengthen π−π interactions with the polymers but also can attract the photoinduced electrons from COP-TF to the surface of CNi 2 P, which contributes to expedite exciton dissociation. As a result, the as-synthesized COP-TF@CNi 2 P achieves a remarkable photocatalytic H 2 production efficiency up to 2500 μmol g −1 h −1 (λ ≥ 400 nm) from seawater and even maintains 92% of initial efficiency after 16 intermittent cycles, which lasts for half a month.

Photocatalytic H2 evolution under solar illumination has been considered to be a promising technology for green energy resources. Developing highly efficient photocatalysts for photocatalytic water splitting is long‐term desired but still challenging. Conjugated polymers (CPs) have attracted ongoing attention and have been considered to be promising alternatives for solar‐driven H2 production due to the excellent merits of the large π‐conjugated system, versatile structures, tunable photoelectric properties, and well‐defined chemical composites. The excellent merits have offered numerous methods for boosting photocatalytic hydrogen evolution (PHE) of initial CP‐based photocatalysts, whose apparent quantum yield is dramatically increased from <1 to >20% in recent five years. According to the photocatalytic mechanism, this review herein systematically summarizes three major strategies for boosting photocatalytic H2 production of CPs: 1) enhancing visible light absorption, 2) suppressing recombination of electron‐hole pairs, and 3) boosting surface catalytic reaction, mainly involving eleven methods, that is, copolymerization, modifying cross‐linker, constructing a donor‐acceptor structure, functionalization, fabricating organic heterojunction, loading cocatalyst, and surface modification. Finally, the perspectives towards the future development of PHE are proposed.

The localized electron density modulation strategy endows an as-synthesized conjugated polymer with improved intrinsic surface catalytic activity with an AQY of 33.5% at 400 nm, which exceeds that of the state-of-the-art CMP materials. state-of-the-art CMP materials.

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