Influences of Metals and Acids on the Photo Reduction of CO2 under Catalysis of TiO2

Conversion of green house CO2 into fuel gas in the presence of reducing agent sources that are Fe and Zn powder, as well as hydrogen ions supplier such as nitric and acetic acids by photo catalytic reduction with water vapor on TiO2 has been studied. The photo reduction was carried out by batch technique, using a UV lamp with a wave length of 290-400 nm, as a photon source. The gasses produced from the photo reduction were determined by gas chromatography. The research results indicate that the photo reduction of CO2 has successfully produced methane as a dominant product. The presence of the metals in addition to be able to improve the methane yield, it is also able to induce ethylene formation. Meanwhile the acids can considerably enhance the methane yield without formation of ethylene. Furthermore, the enhancement is observed to be controlled by mass of the metals, and the acid concentrations. It is also found that Zn and HNO3 show stronger effect in the increasing CO2 photo reduction.

Enhancement of CO_(2)photoreduction efficiency by supporting blue TiO_(2)with photonic crystal substrate

The catalytic performance of TiO_(2)in photoreduction of CO_(2)is limited by its weak absorption in the visible range.In this work,a photonic crystal supported blue TiO_(2)photocatalyst(BTPC)was prepared to demonstrate a 5-6 times higher activity and improved CH_(4)selectivity compared to the BT catalysts deposited on quartz plate.By investigating the influence of the reflection intensity and wavelength of PC support,the superior catalytic performance was found to be originated from the enhanced light absorption of BT and the increased surface electron density brought by the PC support.Based on the study of BT loading on support,multilayer BTPC catalyst was designed to take the most advantage of the transmitted light and achieve a higher conversion of CO_(2)in the unit area of irradiation.

INTRODUCING NH_2 ONTO POLYMERIC FILMS VIA PHOTO-INDUCED C—H BOND TRANSFORMATION WITH PHENOL DERIVATIVES AS BUILDING BLOCKS

A one-step process to introduce both the aromatic and aliphatic primary amino groups with high chemoselectivity was developed. Triplet state acetone abstracts the hydrogen atoms from both the C--H bond of the polymeric film substrate and the O--H bond of phenol which is the building block and the amino group carrier. As a result, two kinds of free radicals, confined carbon-centered chain radicals of the polymer substrate and mobile oxygen-centered phenoxy radicals, were generated. Then the C--O bonds were formed by the coupling reaction between these two kinds of free radicals, p-Tyrarnine and p-aminophenol were used as amino carriers. The successful introduction of amino groups onto LDPE, BOPP and PET film substrates was demonstrated by measurements of water contract angle （CA）, ultraviolet spectra （UV）, X-ray photoelectron spectroscopy （XPS） and fluorescent microscopy. The processing factors, such as the UV-light intensity and irradiation time, concentrations of p-tyramine and p-aminophenol, and the ratio of acetone/water were investigated. The optimized process parameters are as follows： UV light intensity 9500 ~tW/cm2; irradiation time 18 min for BOPP and LDPE, 22 min for PET; the ratio of acetone/water = 1; and concentration ofp-tyramine and p-aminophenol 15% for BOPP and LDPE, 1% for PET. Based on the UV absorbance, the amino groups on the polymeric substrates were estimated to be in the range of 6.3 × 10-6-9.5 × 10-6 mmol/mm2.