No abstract

BACKGROUND Heterogeneous photocatalysis has been demonstrated to be a promising alternative to treating emerging pollutants in wastewater. Phenol, an extremely toxic substance among existing pollutants, can cause long‐term unintended effects when improperly disposed. An effective measure to address this problem is to develop suitable heterojunctions. Among various photocatalyst, titanium dioxide (TiO2) appears to be an excellent photocatalyst in the degradation of organic pollutants. RESULTS Synthetization of well‐constructed heterojunction composite of niobium oxide (Nb2O5) and fibrous silica titania (FST) for enhanced photocatalytic degradation of phenol has been investigated. The photocatalytic performance demonstrated that 5 wt% Nb2O5 loaded on FST (5 Nb/FST) gave the maximum phenol degradation rate (1.70 × 10−2 mM min−1) of 10 mg L−1 phenol at pH 5 using 1000 mg L−1 catalyst within 180 min. Meanwhile, under the same conditions, 1 Nb/FST, FST, 10 Nb/FST and Nb2O5 only delivered 1.51 × 10−2, 1.30 × 10−2, 1.01 × 10−2 and 0.07 × 10−2 mM min−1, respectively. Further phenol photocatalytic degradation routes by 5 Nb/FST reveal that the main intermediates detected are hydroquinone, catechol, maleic, fumaric, and malonic acid. CONCLUSION In this work, 5 Nb2O5/FST composite, as an effective‐performance photocatalyst for phenol degradation, was well‐constructed. The advanced activity can primarily be attributed to the regulated Nb2O5 loading with FST and the effect of Nb/FST microsphere heterojunctions, synergistically. Besides, larger crystallite size, high impurity levels and Si‐O‐Nb and Nb–O–Ti bonds, offers excellent phenol degradation. © 2020 Society of Chemical Industry (SCI)

No abstract

The effect of incorporation of either Zr, Co, Mo or Zn on Pt/HFSM was investigated for the hydroconversion of n-hexane in a pulsed micro-reactor at a temperature range 423-623 K. The acidity of all the studied catalysts were investigated using pyridine adsorption and Fourier Transform Infrared Spectroscopy. The FTIR-pyridine study showed that the catalysts possessed different concentration and strength of both Lewis and Brønsted acid sites. It was revealed that the moderate acid sites distribution on PtZr/HFSM and PtZn/HFSM facilitated the isomerization of the intermediate hexene while the strong acid sites were selective towards cracking reaction. The trend for the bimetallic catalysts studied in n-hexane hydroisomerization is in the order: PtZr/HFSM>PtZn/HFSM>PtMo/HFSM>PtCo/HFSM. The highest activity for hydrocracking and hydrogenolysis were exhibited by PtMo/HFSM and PtCo/HFSM respectively. The PtZr/HFSM exhibited the highest hydroisomerization activity due to the moderate acidity and abundant Lewis acid sites capable of generating protonic acid sites by the hydrogen-spill over phenomena.