Coprecipitation versus chemical vapour deposition to prepare Rh/Ni bimetallic catalysts

Benito, Patricia; Santo, Vladimiro Dal; Grandi, Valentina De; Marelli, Marcello; Fornasari, Giuseppe; Psaro, Rinaldo; Vaccari, Angelo

doi:10.1016/j.apcatb.2015.05.016

Cited by 20 publications

(12 citation statements)

References 76 publications

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“…8. The relative amounts (%) of Ni 0 and NiO, reported in parentheses in Table 5, were in good agreement with those obtained by the EXAFS analysis, indicating that Ni8 sample was more reducible than Ni2 one (as also revealed by CO-DRIFTS analysis 42 ).…”

Section: Ni Speciation In Catalystssupporting

confidence: 82%

“…These species were reduced with time-on-stream for the 8 wt% Ni catalyst, but metallic particle sizes remained almost constant (from 12.1 to 10.5 nm) aer CPO tests. 42 In silicate-containing HT-derived catalysts, the distribution of Ni 2+ species may vary in comparison to conventional carbonate-intercalated catalysts. Some Mg 2+ ions were used in the forsterite phase, thus altering the rock salt/spinel ratio.…”

Section: àmentioning

confidence: 99%

“…13 Aer an activation with time-on-stream a 8 wt% Ni catalyst showed good performances, which slightly depended on the silicate amount; while a 2 wt% Ni catalyst deactivated with time-on-stream by increasing the silicate content. XPS 13 and CO-DRIFT 42 analyses revealed that some Ni 2+ or Ni d+ species were present in the reduced catalyst before CPO tests, decreasing the amount of available Ni 0 active species (also conrmed by H 2 chemisorption). These species were reduced with time-on-stream for the 8 wt% Ni catalyst, but metallic particle sizes remained almost constant (from 12.1 to 10.5 nm) aer CPO tests.…”

Section: Introductionmentioning

confidence: 99%

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The reducibility of highly stable Ni-containing species in catalysts derived from hydrotalcite-type precursors

et al. 2015

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A study was conducted on the speciation and reducibility of Ni in catalysts derived from hydrotalcite-type\ud (HT) precursors intercalated by silicates. Silicate and nickel contents in Ni/Mg/Al HT precursors varied and\ud the products obtained by thermal decomposition in the 773–1373 K range were characterized. Sample\ud properties were related to the amount of silicates and nickel. The former altered the formation of the\ud spinel-type phase and decreased the ratio between MgO and MgAl2O4 phases in which the active\ud species were stabilized. On the other hand, the Ni distribution depended on the Ni-loading. Nicontaining\ud species in the spinel phase were more abundant for high Ni-loaded catalysts, and were\ud readily reduced by H2 treatment at 1023 K, whereas those in the Ni1xMgxO solid solution remained\ud partially unreduced

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Section: Ni Speciation In Catalystssupporting

confidence: 82%

Section: àmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The reducibility of highly stable Ni-containing species in catalysts derived from hydrotalcite-type precursors

et al. 2015

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“…144 Al 2 O 3 could be replaced by other supports such as La 2 O 3 , MgO, SiO 2 , CeO 2 , ZrO 2 , and TiO 2 , which act as promoters and reduce the sintering of the active Ni phase into the support. Different bimetallic Ni catalysts consisting of noble metals such as Pt, 145 Ru, [146][147][148][149] Rh, 150 and Ir 151 as well as non-noble metals such as Co, 149,152,153 Cu, 154 lanthanides (Pr, Gd, Lu), 155 and actinides (Th, U) 156 have been studied. In all cases, the added second metals exhibited increased reducibility and higher coke resistance of the catalysts as observed in the bimetallic Ni catalysts for reforming reactions.…”

Section: Reviewmentioning

confidence: 99%

Ni-based bimetallic heterogeneous catalysts for energy and environmental applications

Zhang

Luque

et al. 2016

Energy Environ. Sci.

629

336

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“…Furthermore, it was discussed that the Ni/Rh phases play the roles of H-adsorption/desorption sites, while the Ni(OH) 2 and Rh 2 O 3 phases catalyze water dissociation, but no direct pieces of evidence were provided for such claims [28]. Moreover, Ni-Rh catalysts were also used for other catalytic reactions [29][30][31][32], showing the versatility of this catalytic system. However, the downside of Rh-containing catalysts is the high price of Rh, caused by its scarcity.…”

Section: Introductionmentioning

confidence: 99%

Enhancement of hydrogen evolution reaction kinetics in alkaline media by fast galvanic displacement of nickel with rhodium – from smooth surfaces to electrodeposited nickel foams

Jovanović

Bijelić

Dobrota

et al. 2021

Preprint

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Energy-efficient hydrogen production is one of the key factors for advancing the hydrogen-based economy. Alkaline water electrolysis is the main route for the production of high-purity hydrogen, but further improvements of hydrogen evolution reaction (HER) catalysts are still needed. Industrial alkaline electrolysis relies on Ni-based catalysts, and here we describe a drastic improvement of HER activity of Ni in alkaline media using several model catalysts for HER obtained upon nickel surface modification in aqueous solution of rhodium salts, when a spontaneous deposition of rhodium takes place based on the chemical displacement reaction 3Ni + 2Rh3+ = 3Ni2+ + 2Rh. In the case of smooth Ni-poly electrodes, HER activity surpasses the activity of Pt-poly already after 30 s of exchange with Rh. SEM analysis showed that Rh is uniformly distributed, while surface roughness changes within 10%, agreeing with electrochemical measurements. Furthermore, XPS analysis has shown effective incorporation of Rh in the surface, while DFT calculations suggest that hydrogen binding is significantly weakened on the Rh-modified Ni surfaces. Such tuning of the hydrogen binding energy is seen as the main factor governing HER activity improvements. The same galvanic displacement protocols were employed for nickel foam electrodes and electrodeposited Ni on Ti mesh. In both cases, somewhat longer Rh exchange times are needed to obtain superior activities than for the smooth Ni surface, but up to 10 min. HER overpotential corresponding to −10 mA cm−2 for nickel foam and electrodeposited Ni electrodes, after modification with Rh, amounted to only −0.07 and −0.09 V, respectively. Thus, it is suggested that a fast spontaneous displacement of Ni with Rh could effectively boost HER in alkaline media with minor cost penalties compared to energy saving in the electrolysis process.

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Coprecipitation versus chemical vapour deposition to prepare Rh/Ni bimetallic catalysts

Cited by 20 publications

References 76 publications

The reducibility of highly stable Ni-containing species in catalysts derived from hydrotalcite-type precursors

The reducibility of highly stable Ni-containing species in catalysts derived from hydrotalcite-type precursors

Ni-based bimetallic heterogeneous catalysts for energy and environmental applications

Enhancement of hydrogen evolution reaction kinetics in alkaline media by fast galvanic displacement of nickel with rhodium – from smooth surfaces to electrodeposited nickel foams

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