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-C 3 N 4 (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.