Borohydride reduction of the perrhenate ion

Pacer, Richard A.

doi:10.1016/0022-1902(73)80213-1

Cited by 12 publications

(10 citation statements)

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“…Results shown in Figure 2 indicate that these Re species are much more strongly associated with the Pd-AC surface than is ReO 4 -, particularly at Re contents exceeding the ReO 4 -concentration that corresponds to surface saturation (∼5 wt % Re for 2 g/L Pd-AC) ( Figure 4B). These results are consistent with previous studies, where reduction of ReO 4 -was reported to result in a +4 oxidation state of Re (24), and where Re in the +5 oxidation state is reported to be important in oxygen atom transfer reactions (13,15).…”

Section: Perchlorate Reduction and Perrhenate Leaching Withsupporting

confidence: 95%

Influence of Rhenium Speciation on the Stability and Activity of Re/Pd Bimetal Catalysts used for Perchlorate Reduction

Choe

Shapley

Strathmann

et al. 2010

Environ. Sci. Technol.

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Recent work demonstrates reduction of aqueous perchlorate by hydrogen at ambient temperatures and pressures using a novel rhenium-palladium bimetal catalyst immobilized on activated carbon (Re/Pd-AC). This study examines the influence of Re speciation on catalyst activity and stability. Rates of perchlorate reduction are linearly dependent on Re content from 0-6 wt %, but no further increases are observed at higher Re contents. Surface-immobilized Re shows varying stability and speciation both in oxic versus H(2)-reducing environments and as a function of Re content. In oxic solutions, Re immobilization is dictated by sorption of the Re(VII) precursor, perrhenate (ReO(4)(-)), to activated carbon via electrostatic interactions. Under H(2)-reducing conditions, Re immobilization is significantly improved and leaching is minimized by ReO(4)(-) reduction to more reduced species on the catalyst surface. X-ray photoelectron spectroscopy shows two different Re binding energy states under H(2)-reducing conditions that correspond most closely to Re(V)/Re(IV) and Re(I) reference standards, respectively. The distribution of the two redox states varies with Re content, with the latter predominating at lower Re contents where catalyst activity is more strongly dependent on Re content. Results demonstrate that both lower Re contents and the maintenance of H(2)-reducing conditions are key elements in stabilizing the active Re surface species that are needed for sustained catalytic perchlorate treatment.

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Section: Perchlorate Reduction and Perrhenate Leaching Withsupporting

confidence: 95%

Influence of Rhenium Speciation on the Stability and Activity of Re/Pd Bimetal Catalysts used for Perchlorate Reduction

Choe

Shapley

Strathmann

et al. 2010

Environ. Sci. Technol.

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“…One of the main drawbacks for the development of methods for the synthesis and application of Re NPs is the instability of the Re colloids generated by chemical reduction. Early studies on the reduction of the perrhenate ion in water indicated the uncertain nature of the reduction products due to oxidation by air and the occurrence of mixed oxidation states [17]. Mucaloet al [18,19] studied the preparation of Re colloids by chemical reduction of K 2 ReCl 6 in water by N 2 H 4 and NaBH 4 , both in the absence and presence of protective agents, observing that the NPs are highly susceptible to rapid reoxidation to oxidation states that are even higher than that of the starting hexachlororhenate ion.…”

Section: Introductionmentioning

confidence: 99%

Colloidal and microemulsion synthesis of rhenium nanoparticles in aqueous medium

Bedia

Calvo

Lemus

et al. 2015

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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“…Though there are many potential applications for Re NPs as mentioned above, the preparation of Re NPs is not much studied in the literature. − One of the major problems of preparing zerovalent Re NPs is its readiness for simultaneous oxidation in aqueous colloidal solution. Hence, so far, wet chemical synthesis of stable Re NPs has been a really challenging and hard task.…”

Section: Introductionmentioning

confidence: 99%

“…Hence, so far, wet chemical synthesis of stable Re NPs has been a really challenging and hard task. Several synthesis methods have been reported to prepare metallic Re NPs in solution-based routes such as wet-chemical reduction, − ,− in reverse micelles, , and alcohol-assisted reduction . The reduction of Re salts in water generates many unknown products due to its oxidation in air or water and results in oxidized products rather than metallic Re NPs .…”

Section: Introductionmentioning

confidence: 99%

“…Several synthesis methods have been reported to prepare metallic Re NPs in solution-based routes such as wet-chemical reduction, − ,− in reverse micelles, , and alcohol-assisted reduction . The reduction of Re salts in water generates many unknown products due to its oxidation in air or water and results in oxidized products rather than metallic Re NPs . Mucalo et al synthesized Re NPs by the chemical reduction of K 2 ReCl 6 salt in water but observed a rapid oxidation of the synthesized NPs .…”

Section: Introductionmentioning

confidence: 99%

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Polymer Encapsulated Self-Assemblies of Ultrasmall Rhenium Nanoparticles: Catalysis and SERS Applications

Kundu

Dai

et al. 2017

ACS Sustainable Chem. Eng.

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Ultrafast formation of stable and self-assembled rhenium (Re) nanoparticles (NPs) using a poly allylamine hydrochloride (PAH) scaffold within 120 s of wet-chemical reaction at room temperature in aqueous solution has been reported. The average diameters of the two different sets of Re NPs synthesized are ∼0.7 ± 0.25 and ∼1.7 ± 0.3 nm, which can be easily achieved by controlling the polymer to Re7+ molar ratio. The small-size Re NPs are formed in solution, self-assembled together to form the chain-like or necklace-like structure. The synthesized Re NPs were used in two different potential applications, such as in catalysis and in surface-enhanced Raman scattering (SERS) studies. Catalysis study was done for 4-nitroaniline (4-NA) reduction with excess NaBH4 taking two different sets of Re NPs as catalyst. The highest catalytic rate for nitroaromatics reduction ever reported of ∼1.52 × 10–1 min–1 has been observed with large-size Re NPs as catalyst. In SERS, methylene blue (MB) was used as a Raman probe molecule. Strong SERS enhancements were observed with both sets of Re NPs due to their ultrasmall size, narrow interparticle gap, and self-assembled structure in PAH scaffold. These closely tethered and self-assembled Re NPs generated more surface active “hot spots” that resulted in good SERS enhancement. The present synthesis route is easy, cost effective, and fast and can generate stable Re NPs which could further be applied in interdisciplinary fields other than catalysis and SERS in the near future.

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Borohydride reduction of the perrhenate ion

Cited by 12 publications

References 1 publication

Influence of Rhenium Speciation on the Stability and Activity of Re/Pd Bimetal Catalysts used for Perchlorate Reduction

Influence of Rhenium Speciation on the Stability and Activity of Re/Pd Bimetal Catalysts used for Perchlorate Reduction

Colloidal and microemulsion synthesis of rhenium nanoparticles in aqueous medium

Polymer Encapsulated Self-Assemblies of Ultrasmall Rhenium Nanoparticles: Catalysis and SERS Applications

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