Directing Ni/Al layered double hydroxides nanosheets on tubular graphite carbon nitride for promoted photocatalytic hydrogen production

Constructing heterojunctions via in-situ growth or mechanical mixing have been widely used for improving the photogenerated carrier separation and photocatalytic activity. However, interface transfer impedance and the charge transfer channels of heterojunction prepared by in-situ method are rarely discussed. In this work, we use tubular g-C₃N₄ (TCN) as the basic photocatalyst and in-situ growth of nickel/aluminum layered double hydroxide (LDH) nanosheets as co-catalyst on the surface of TCN (TCN@Ni/Al-LDH) to show the advantage of the in-situ constructing heterojunction for highly enhanced photocatalytic hydrogen production. The results show that the TCN@Ni/Al-LDH-60 exhibits the best hydrogen production performance of 1428 μmol h⁻¹ g⁻¹, which is 53.3 and 21.33 times higher than that of TCN and mechanical prepared TCN/Ni/Al-LDH-60. For the first time, we propose a statistics model to reveal that the contact area of the heterojunction TCN@Ni/Al-LDH-60 is 2.88 times that of TCN/Ni/Al-LDH-60. This largely increases the charge transfer channels for the photogenerated carrier transport. In addition, the in-situ growth of TCN@Ni/Al-LDH composites increases the active sites, which improves the utilization efficiency of the photogenerated electrons. This study would shed some light on analyzing the in-situ constructing heterojunction photocatalysts for efficient photocatalytic hydrogen production through photocatalytic water splitting.