Lowering the synthesis temperature of Ni2P/SiO2 by palladium addition

Abstract

The addition of small amounts of palladium (0.1%, 0.5% and 1.0% w/w) to a Ni x P y O z /SiO 2 sample led to a decrease of $200 K in the synthesis temperature of Ni 2 P/SiO 2 , allowing synthesis to proceed at 723 K. In situ X-ray diffraction (XRD) and X-ray absorption near-edge structure (XANES) experiments demonstrated that the phosphate ? phosphide transformation started at approximately 673 K, and the total time to reduce the phosphate phase was decreased by the presence of palladium. Based on the in situ P K-edge XANES experiments and CO chemisorption uptakes, it was proposed that, depending on the amount of palladium incorporated, the final catalysts present different degrees of reduction, thereby impacting catalytic activity. An increase in activity was observed for the palladium-containing samples during time on stream, which might be associated with the formation of a phosphosulfide active species. The extent of the phosphosulfide species formation was dependent on the degree of reduction.

Preparation of Ni 2 P/Al 2 O 3 by temperature-programmed reduction of a phosphate precursor with a low P/Ni ratio

“…Yang and Prins [14] prepared a Ni 2 P/Al 2 O 3 catalyst by treating a metallic Ni/Al 2 O 3 precursor with a 10% PH 3 /H 2 mixture at 250°C. However, according to Da Silva et al [15], these alternative routes have disadvantages that may limit their application. This means that currently the TPR method is still the most feasible way to prepare supported Ni 2 P catalysts.…”

Synthesis of an yttrium-modified bulk Ni2P catalyst with high hydrodesulfurization activity

“…1, XRD diffractograms of Ni 2 P and Y x Ni 2 P precursor present broad feature peak centered at 2θ = 32°, which can be assigned to the amorphous Ni x P y O z phases [19]. For all of the catalysts, the peaks at 2θ = 40.6°, 44.5°, 47.1°, and 54.1°(PDF no.…”

NiMo catalysts supported on graphene-modified mesoporous TiO2 toward highly efficient hydrodesulfurization of dibenzothiophene

“…Among of them ,CO uptake is undertaken over the spent catalyst at room temperature to evaluate the active sites on catalyst. The k HDS and TOF are calculated by K HDS and , respectively, where F is the rate of DBT fed into the reactor (µmol s -1 ), w is mass of catalyst (g), y is the conversion of DBT and M is the active sites deposited on catalyst decided by CO uptake [49,60]. As can be seen in Table 3, the higher conversion of DBT corresponding to a higher value of K HDS , and the NiMo/TGC-0.5 catalyst shows the maximum of 0.76.…”