Enhanced Hydrogen Production from DNA‐Assembled Z‐Scheme TiO₂–CdS Photocatalyst Systems

Abstract

A wide range of inorganic nanostructures have been used as photocatalysts for generating H2. To increase activity, Z-scheme photocatalytic systems have been implemented that use multiple types of photoactive materials and electron mediators. Optimal catalysis has previously been obtained by interfacing different materials through aggregation or epitaxial nucleation, all of which lowers the accessible active surface area. DNA has now been used as a structure-directing agent to organize TiO2 and CdS nanocrystals. A significant increase in H2 production compared to CdS or TiO2 alone was thus observed directly in solution with no sacrificial donors or applied bias. The inclusion of benzoquinone (BQ) equidistant between the TiO2 and CdS through DNA assembly further increased H2 production. While the use of a second quinone in conjunction with BQ showed no more improvement, its location within the Z-scheme was found to strongly influence catalysis.

Assembling Polyoxo‐Titanium Clusters and CdS Nanoparticles to a Porous Matrix for Efficient and Tunable H2‐Evolution Activities with Visible Light

“…Photocatalytic hydrogen evolution by water splitting has been recognized as one of the most promising solutions to the global energy and environment crisis, owing to its renewable solar energy source and clean chemical fuel product . Cadmium sulfide (CdS), with excellent visible‐light response and appropriately positioned conduction band, has been investigated extensively as a photocatalyst for H 2 evolution .…”

Metal–Organic Framework‐Derived ZnO/ZnS Heteronanostructures for Efficient Visible‐Light‐Driven Photocatalytic Hydrogen Production

“…In recent years, numerous efforts have been devoted to the design and fabrication of heterojunction photocatalysts for tailoring band gaps and improving the photocatalytic activity . Two most‐used synthesis methods, interfacing different materials via aggregation, and epitaxial nucleation of one material on the surface of the other, have made a big contribution to this field but tend to lower the accessible active surface area and reduce the number of active sites. Therefore, it is essential to exploit new methods for the synthesis of heterojunctions, especially nanosized heterojunctions, for photocatalytic hydrogen evolution.…”

A Novel Green TiO2 Photocatalyst with a Surface Charge‐Transfer Complex of Ti and Hydrazine Groups

“…From Figure B and C, no distinct change was observed in Ti 2p and O 2p spectra in both the white and green TiO 2 . Two peaks at 458.4 and 464.1 eV were ascribed to the Ti 2p3/2 and Ti 2p1/2 of Ti 4+ ions, and no Ti 3+ or other lower valence species was observed because no shoulders were observed at lower binding energy . One main peak at 530.0 eV and a small shoulder peak at 532.0 eV were attributed to the lattice oxygen and some hydroxyl groups, likely from adsorbed water on the surface, respectively .…”