The Nature of PH₃ Decomposition Reaction over Amorphous CoNiBP Alloy Supported on Carbon Nanotubes

Abstract

The carbon nanotubes (CNTs) supported amorphous CoNiBP catalyst is synthesized by means of induced electroless-plating method. The morphology, structure, and composition of the catalyst are characterized using a number of analytical instrumentations including transmission electron microscopy, X-ray diffraction, BET surface area measurement, and inductively coupled plasma. The activity of the catalyst in phosphine decomposition reaction is measured and correlated with its surface and structural properties. The characterization results show that the amorphous CoNiBP alloy nanoparticles, having average diameters of about 5−9 nm and 8−12 nm, are uniformly distributed inside and on the surface of CNTs, respectively. During phosphine decomposition reaction, some of phosphorus atoms migrate onto the CoNiBP particles, forming crystalline CoP phase which acts as the dominant active phase for phosphine decomposition reaction. Furthermore, the CoNiBP/CNTs catalyst exhibits high activity and stability in phosphine decomposition reaction. When operated in a fixed-bed reactor at 380 °C, single-pass phosphine conversion of about 99.7% can be achieved.

Catalytic Decomposition of Toxic Chemicals Over Iron Group Metals Supported on Carbon Nanotubes

“…Table shows that the molar ratios of P/M in the Fe 2 O 3 /CNTs-S, Co 3 O 4 /CNTs-S, Co/CNTs-S, NiO/CNTs-S, and Ni/CNTs-S are 1.2, 1.3, 1.2, 2.3, and 2.5 respectively, approximating to the stoichiometry of FeP, CoP, and NiP 2 . The result is consistent with our previous studies on cobalt metal and cobalt alloy prepared by impregnation and induced electroplating technique. , …”

“…In order to create more defects and holes, increase BET surface area, and develop hydrophilic surface groups on the walls of the CNTs, the CNTs were pretreated before the active components were impregnated. The details about the pretreatment procedure are described in our previous publication . The CNTs used in this study are aligned multiwall carbon nanotubes which were purchased from Shenzhen Nanotech Co., Ltd., China.…”

“…However, small amounts of PH 3 , P 2 O 5 , and H 3 PO 4 acid mist are inevitably emitted, causing both environmental and economic concern. In the past decades, a number of publications have been dedicated to the removal of PH 3 using gas–solid adsorption techniques, wet scrubbing, and catalytic decomposition methods . Adsorption and wet scrubbing techniques are inefficient due to low capacity and high operating cost.…”

“…In the absence of a catalyst, PH 3 decomposition occurs at temperatures higher than 600 °C. Our recent study has shown that Co presented in either alloy or metal catalysts was phosphized by a small amount of P in the initial stage of reaction, forming cobalt phosphide, which functions as active phase of the catalyst. , Metal phosphides are widely used in catalytic processes, including hydrotreating, hydrodechlorination, hydrazine decomposition, and so forth. , However, there has been little research on using iron group metals or metal oxides in PH 3 decomposition reaction.…”

Chemoselective Hydrogenation of Benzoic Acid over Ni–Zr–B–PEG(800) Nanoscale Amorphous Alloy in Water

“…In recent years, nanoscale amorphous alloys have been widely used in the field of catalysis and hydrogen storage due to their excellent physical and chemical properties, such as short-range order, long-range disorder, and good dispersion. − In particular, metal-doped Ni–B amorphous alloys have attracted much attention owing to their excellent catalytic performance, low cost, and environmentally benign nature. − For instance, Li et al have reported that Co-doped Ni–B amorphous alloys exhibited higher activity and chemoselectivity than the undoped system in the liquid phase hydrogenation of acetonitrile, and the effect of the quantity of Co was investigated in detail . Although addition of metals to amorphous alloys can increase dispersion and therefore their activities, agglomeration phenomena still exist sometimes leading to decreased activity, so it continues to be of great importance to find other effective modifiers. , Accordingly, polymers have been employed to prevent agglomeration of active components in catalysts, resulting in better dispersion and higher activity in catalytic hydrogenation. − For instance, Liaw et al have reported that the particle sizes of a Co–Ni–B catalyst can be effectively controlled by using polyvinylpyrrolidone (PVP) as a modifier and the polymer-modified catalyst was more active than the unmodified one in the hydrogenation of unsaturated aldehydes .…”