Synergistic effect of g-C3N4, Ni(OH)2 and halloysite in nanocomposite photocatalyst on efficient photocatalytic hydrogen generation

Abstract

Here, we develop a strategy to improve the visible-light-driven photocatalytic hydrogen evolution activity of g-C3N4 by compositing it with low-cost Ni(OH)2 nanoplatelets and inexpensive and earth-abundant halloysite nanotubes. The Ni(OH)2@g-C3N4/halloysite nanocomposite photocatalysts with different amounts of Ni(OH)2 (0.5–10 wt%) were prepared, and a synergistic effect of Ni(OH)2 platelets and halloysite nanotubes on physicochemical properties and photocatalytic hydrogen evolution activity of g-C3N4 was investigated. As expected, the Ni(OH)2@g-C3N4/halloysite nanocomposite photocatalyst prepared with 1 wt% Ni(OH)2 exhibited the highest photocatalytic hydrogen evolution rate (18.42 μmol h−1) which is much higher than that of g-C3N4 (0.43 μmol h−1) and Ni(OH)2@g-C3N4 (9.12 μmol h−1). Such enhancement in photocatalytic activity of Ni(OH)2@g-C3N4/halloysite nanocomposite photocatalyst is attributed to efficient transfer of photogenerated electrons from the g-C3N4 to Ni(OH)2 cocatalyst interface and trapping of photogenerated holes on the negatively charged surfaces of halloysite nanotubes. In addition, adsorption affinity of the water and methanol molecules was modeled using different surfaces of Ni(OH)2, halloysite-7Å, and g-C3N4 and it is found that combining the g-C3N4 with halloysite-7Å and Ni(OH)2 can significantly improve the adsorption of water and methanol molecules on the surface of the developed nanocomposite. This study offers a simple approach for developing an efficient and inexpensive nanocomposite for effective and applied photocatalytic water splitting methodology for hydrogen production and other possible optoelectronic and photocatalytic applications.