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Graphical abstract The corner site C atoms in g-C 3 N 4 are partially repalced by P heteroatoms using a simple thermal phosphorization method. The modified structure of g-C 3 N 4 leads to the extended light absorption, increased energetic photo-induced electrons, highly hydrophilic surface, and enhanced charge transfer ability, enabling enhanced photocatalytic hydrogen evolution activity in contrast to the pristine one. Highlights • The corner-site C atoms are partially replaced by P atom in g-C 3 N 4. • g-C 3 N 4 (P) shows a narrowed band gap with upshifted conduction band edge. • g-C 3 N 4 (P) is more hydrophilic than the pristine one to absorb reactant molecule. • Replacing corner site C atoms with P atoms enhances the charge separation and transfer. Abstract Modifying the structure of photocatalyst to tune its electronic and physicochemical properties is an effective approach for efficient photocatalysis. Herein, we modify the structure of g-C 3 N 4 by partially replacing the corner site C atom with P heteroatom via a simple thermal phosphorization method. Comparing with the pristine g-C 3 N 4 , the g-C 3 N 4 after phosphorization shows an improved photocatalytic hydrogen activity, which is attributed to the narrowed bandgap and the upshifted conduction band edge, enhanced separation and transfer of photogenerated charges, and highly hydrophilic surface absorbing reactant molecule for photocatalysis. Various experimental characterizations are conducted to systemically explore the underlying essential mechanism behind the superior photocatalytic performance of g-C 3 N 4 with phosphorization treatment. This work provides a simple approach to modifying the structure of g-C 3 N 4 , which could be applied to other semiconductors for designing photocatalyst with unique structure and enhanced activity. [ABSTRACT FROM AUTHOR]

• Superficial potential trap is formed near Co atom in g-C 3 N 4 (Co). • Co atom act as a bridge to connect g-C 3 N 4 and Pt NPs. • The bridging effect of Co atom can rapidly transfer the photo-induced electrons. • The water molecule is more easily dissociated by Co atom bridge. • The photocatalytic activity of g-C 3 N 4 (Co)-Pt is 145.8 times that of pristine g-C 3 N 4. To achieve a highly efficient charge transfer and separation for photocatalysis, we propose a bridging effect to construct a direct charge transfer path in g-C 3 N 4 via introducing Co atoms into the nitride pores of g-C 3 N 4 to trigger a superficial potential trap. By utilizing such superficial potential trap, the Co atom can bridge the ultrafine Pt NPs and g-C 3 N 4 as catalyst for hydrogen evolution reaction. The bridging effect of Co heteroatom in g-C 3 N 4 (Co)/Pt can rapidly transfer the photo-generated electrons on g-C 3 N 4 to Pt NP surface, thus significantly improving the charge separation efficiency. Moreover, the water molecule is more easily dissociated by Co atom bridge, enabling its kinetics favorable for photocatalytic hydrogen reaction. As a consequence, the photocatalytic H 2 evolution rate of g-C 3 N 4 (Co)/Pt reaches 7.145 mmol g−1 h−1 with an excellent apparent quantum efficiency of 19.0% at 420 nm, which is 145.8 times than that of pristine g-C 3 N 4. [ABSTRACT FROM AUTHOR]

One of the bottlenecks for photocatalytic H 2 generation is the severe recombination of photoexcited charge carriers in photocatalysts. As an effective approach, constructing heterojunction with type II band alignment has been applied for efficient charge separation in photocatalysts during the photocatalytic process. By compositing g-C 3 N 4 and P25 as a model photocatalyst, the limited charge separation efficiency and random charge transfer paths are discovered in this conventional type II heterostructured g-C 3 N 4 /P25. In order to overcome these shortcomings in g-C 3 N 4 /P25, we designed a type II heterostructured photocatalyst with oriented transfer path for photo-excited charges during the real photocatalysis process via a one-pot synthesis strategy, in which the separation efficiency was much improved. The as-prepared g-C 3 N 4 /P25(N)-Pd photocatalyst exhibits a tremendously enhanced photocatalytic activity, which is 8.7 and 24.5 times that of g-C 3 N 4 under visible light and full wave light irradiation, respectively. [ABSTRACT FROM AUTHOR]

It is an effective approach to regulate the structure of photocatalysts by introducing the heteroatoms into the lattice for extended light absorption and enhanced charge separation. In this work, the P atoms were introduced to substitute the corner C atoms of g-C 3 N 4 by calcinating the melamine-phytic acid derived supramolecular with high-density phosphate groups, which is synthesized by hydrothermal method. The intermediate state produced by the introduction of P atoms leads to the enhanced light absorption of P–CN (7.2g-IP6) with a negative shifted conduction band position, which benefits the photocatalytic hydrogen reaction kinetically. Moreover, the electron transferred from P atom to the surrounding N atoms results in the positively charged P center, which could act as Lewis acid site. Such formed Lewis acid site at positively charged P center together with the Lewis base sites, such as amine or imine groups in P–CN, makes it easier to separate photogenerated charges, thus enabling the P–CN (7.2g-IP6) to exhibit an enhanced photocatalytic hydrogen rate of 2.743 mmol·g−1·h−1, which is about 6.77 times that of pristine g-C 3 N 4 (0.405 mmol·g−1·h−1). This work provides an alternative approach to regulating the structure of photocatalysts. • Melamine-Phytic Acid Derived Supramolecular (MP) was obtained by hydrothermal method. • P atoms was in situ introduced into g-C 3 N 4 by calcinating the MP precursor. • The P doped g-C 3 N 4 showed extended absorption and enhanced charge separation. • The P doped g-C 3 N 4 exhibited superior photocatalytic performance than pristine CN. [ABSTRACT FROM AUTHOR]

• Triphenylphosphine (PPh3) was used for the phosphorization of g-C 3 N 4. • g-C 3 N 4 (PPh3) showed extended light absorption and promoted charge separation. • g-C 3 N 4 (PPh3) exhibited higher photocatalytic activity than g-C 3 N 4. It is an effective strategy to regulate the structure of photocatalysts for enhanced photocatalytic hydrogen evolution. In this work, a facile method was developed to introduce P atoms into g-C 3 N 4 via the thermal calcination treatment. In contrast to pristine g-C 3 N 4 , the obtained P-CN(PPh3) exhibited a negative shift of conduction band edge with enhanced light absorption after the introduction of P atoms into g-C 3 N 4 , thus benefiting the photocatalytic hydrogen evolution. Moreover, the introduction of P element in g-C 3 N 4 can also improve the charge separation during the photocatalytic hydrogen reaction, significantly accelerating the photocatalytic hydrogen production rate of P-CN(PPh3). [ABSTRACT FROM AUTHOR]