Enhanced photocatalytic activity of Bi12O17Cl2 nano-sheets via surface modification of carbon nanotubes as electron carriers

A novel carbon nanotubes modified Bi₁₂O₁₇Cl₂ composite (CNTs/Bi₁₂O₁₇Cl₂) was prepared via hydrothermal method. The chemical structures, morphologies, optical properties of the synthesized samples were revealed by XRD, XPS, SEM, TEM, BET and UV-vis DRS measurements. The photocatalytic activity of the CNTs/Bi₁₂O₁₇Cl₂ composite was evaluated with degradation reaction of rhodamine B (RhB) under visible light. CNTs/Bi₁₂O₁₇Cl₂ exhibited improved photocatalytic activity in comparison with pure Bi₁₂O₁₇Cl₂, and kept favorable stability and recyclability in the reaction. The relatively high photocatalytic activity of CNTs/Bi₁₂O₁₇Cl₂ resulted from the enhanced separation efficiency of photo-induced charges, which were revealed by the photoluminescence spectra and transient photocurrent measurements. CNTs loaded at the surface of Bi₁₂O₁₇Cl₂ sheets acted as electron carriers to efficiently transfer the photoinduced electrons, namely to promote the separation of photoinduced electrons and holes, thus improving the photocatalytic activity of the composite materials. At last, a possible photocatalytic reaction mechanism over the CNTs/Bi₁₂O₁₇Cl₂ composite was proposed based on the results of trapping experiment, ESR measurements and the band energy analysis.

Louis Nico Marie Duysens (March 15, 1921-September 8, 2015): a leading biophysicist of the 20th century

Louis Nico Marie (L. N. M.) Duijsens (Duysens) was one of the giants in the biophysics of photosynthesis. His PhD thesis "Transfer of Excitation Energy in Photosynthesis" (Duysens, 1952) is a classic; he introduced light-induced absorption difference spectroscopy to photosynthesis research and proved the existence of reaction centers, introducing advanced methods from physics to understand biological processes. Further, it is his 1959-1961 seminal work, with Jan Amesz, that provided evidence for the existence of the series scheme for the two light reactions in oxygenic photosynthesis. In one word, he was one of the master biophysicists of the 20th century-who provided direct measurements on many key intermediates, and made us understand the intricacies of photosynthesis with a simplicity that no one else ever did. We present here our personal perspective of the scientist that Lou Duysens was. For an earlier perspective, see van Grondelle and van Gorkom (Photosynth Res 120: 3-7, 2014).