Catalytic Decomposition of CF4 over AlPO4-Based Catalysts

Abstract

The most stable perfluorocarbon, CF4, was decomposed to CO2 at above 550 °C in the presence of water vapor over AlPO4 in which 10 atomic % of Al ions are substituted by Ce. Catalytic activity slightly decreased within first 50 h and then took a stationary state for succeeding 50 h. No changes in the structure of catalyst were observed after 100 h reaction. Mg pyrophosphate and phosphates of Ca, B, Fe, Zn, Bi, and Ni were not active up to 700 °C. The addition of Ce, La, Pr, Nd, Gd, Yb, Er, or Y into AlPO4 increased the catalytic activity.

Metal Phosphate-Supported Pt Catalysts for CO Oxidation

“…In the literature, some metal carbonates, phosphates, and sulfates have been used as supports to load metals [2]. From the examples on the catalytic applications of metal phosphate-based catalysts cited in the Introduction section [4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,…”

“…In a classic book written by Tanabe, Misono, Ono, and Hattori, metal phosphates are highlighted as a new family of solid acids showing some promising applications in heterogeneous catalysis [3]. Metal phosphates can be used as catalysts directly, for instance, in the partial oxidation of propane [4], oxidative dehydrogenation of isobutane to isobutene [5,6,7], oxidative dehydrogenation of ethylbenzene to styrene [8], dehydration of cyclohexanol and 1-methylcyclohexanol [9,10,11], retro-Prins reaction [12,13], terpene rearrangements [14], alkylation of anisole with alcohols [15], dehydrofluorination of CF 3 CH 3 into CF 2 CH 2 [16,17], hydrolysis of CCl 2 F 2 [18,19,20], decomposition of CF 4 [21,22], decomposition of CH 2 FCF 3 [23], decomposition of chlorobenzene [24], decomposition of SF 6 [25,26], and hydrolysis of NF 3 [27]. …”

The catalytic decomposition of CF4 over Ce/Al2O3 modified by a cerium sulfate precursor

“…Among these methods, catalytic decomposition has been suggested as the most practical and economical method for reducing PFCs [14][15][16][17]. Takita et al reported that CF 4 , the most stable compound in PFCs, was decomposed by hydrolysis at 700 • C on selected metal phosphate catalysts, such as aluminum phosphate, and its mixtures with rare earth metal phosphates [18,19]. These phosphate catalysts including AlPO 4 have surprisingly long lifetimes and produce excellent results in practical applications [20].…”

Adsorption equilibrium of sulfur hexafluoride on multi-walled carbon nanotubes

“…Because the process/equipment and material modifications are not currently practical, add-on-control approaches are the most available and cost-effective methods at present. Several studies have addressed the abatement/destruction methods such as thermal destruction [3], catalytic decomposition [4], plasma abatement [5], electrochemical reduction [6], photodegradation [7,8] and other advanced or combined abatement processes [9]. However, all of these are very costly and by-products emitted from some methods are harmful to human health and the environment [10].…”