Characterization of Ni‐Coated WS₂ Nanotubes for Hydrodesulfurization Catalysis

Abstract

A reactivity screening of new nano‐hydrodesulfurization (HDS) catalysts was conducted using an ambient pressure flow reactor as well as ultra‐high vacuum kinetics techniques. Thiophene was used as a probe molecule. Clean multiwall WS2 nanotubes (INT‐WS2) as well as Ni‐ and Co‐coated INT‐WS2 were considered. In addition, undoped MoS2 and Re‐doped nanoparticles with fullerene‐like structures were studied. Commercial Ni and Co HDS catalysts from Haldor Topsoe (Denmark) as well as “nano MoS2” from Impex Corp. (USA) were considered as reference materials. The lab‐synthesized and commercial systems broke down thiophene into quite similar non‐sulfur containing products, as identified by a gas chromatograph. The Ni and Co promoted catalysts showed similar thiophene conversion rates. Although the commercial catalysts had larger thiophene conversion rates than the laboratory‐synthesized systems, the Re‐doped nano‐HDS catalyst showed quite low rates of formation of H2S, an undesirable by‐product.

Direct Synthesis of Palladium Catalyst on Supporting WS2 Nanotubes and its Reactivity in Cross‐Coupling Reactions

“…The high yield obtained in both reaction mechanisms may suggest that the INT‐WS 2 play an active role rather than being just a passive substrate for the Pd nanoparticles. It was already shown that INT decorated with Ni NPs have an improved catalytic activity for hydrodesulfurization compared with pristine nanotubes . While there are studies regarding the influence of size and shape of Pd NPs on the catalytic activity, the longstanding question on the role of the support in catalytic reactions and in the case of the nano‐sized substrate has been investigated in several specific cases only.…”

“…Additionally, the nanotubes were broken into nanoflakes using sonochemistry in order to break S−W bonds and provide for more active edge sites . The proposed catalytic reactions were hydrodesulfurization, photocatalysis, and electrocatalysis.…”

Thin WS2 nanotubes from W18O49 nanowires

“…Attention has also been drawn to other inorganic nanotubes since then owing to their interesting properties. Substantial progress has been made and demonstrated that MoS 2 and WS 2 nanotubes have great potential for applications in scanning probe microscopy [4,5], lubrication [6], catalysis [7,8], field-effect transistors [9], nanocomposites [10], and energy storage [11,12].…”

Two facile routes for functionalization of WS2 nanotubes with silver nanoparticles

“…Surface modification of NT-WS 2 with inorganic nanoparticles expands application areas of disulfide nanotubes. Co@NT-WS 2 [22] and Ni@NT-WS 2 [23] nanocomposites effectively catalyze hydrodesulfurization reactions of thiophene and similar compounds. Additionally, Co@NT-WS 2 is considered as a promising visible-light photocatalyst [24].…”