Manipulating the nickel shape and catalytic performance: from spheres to chains to urchins

Abstract

Different nickel particle morphologies, including spheres, chains and urchins, were achieved in ethylene glycol solvent upon simply tuning both the amount of water and NaOH. The synthesis route was based on a routine solvothermal technique, in which nickel chloride and hydrazine hydrate were the nickel source and reductant, respectively. The shape transformation might be induced by an accelerated reaction rate and a change of the polarity of the solvent. Owing to the various morphology, these three kinds of nickel particles presented different catalytic performance. The reduction of 4-nitrophenol by NaBH 4 as a typical catalytic model revealed that the urchin-like nickel particles behaved with the highest catalytic effect because of their unique structure with tips on the surface, which endowed much more active sites for the catalytic reaction. The good magnetic properties allowed these nickel particles to be readily recycled after application and they presented a much high cycling stability.

Anchoring gold nanoparticles inside polyaniline shells with magnetic cores for the enhancement of catalytic stability

“…In our experiment, a thin layer of PANI is coating on the outside of the AuNPs, where the porous structure of the PANI layer allows the transport of the molecules or ions to contact with the AuNPs. 35 The obtained k values for Fe 3 O 4 @Au-PANI, Fe 3 O 4 @Au-PANI-II and Fe 3 O 4 @SiO 2 @Au are 0.124, 0.023 and 0.673 min -1 , respectively. The typical time-dependent evolution of UV-Vis absorption spectra of the catalysis system using Fe 3 O 4 @Au-PANI particles is presented in Figure 5.…”

Achieving MnO2 Nanosheets through Surface Redox Reaction on Nickel Nanochains for Catalysis and Energy Storage

“…Furthermore, as expected, the other two control samples, Ni@MnO 2 ‐5 and Ni@MnO 2 ‐20 presented complete degradation times of 42 and 48 min, respectively (Figure S11a and b). Owing to the excess of NaBH 4 compared to 4‐NP, the reaction can be regarded as pseudo‐first‐order . Based on the slope of the linear fit of ln( c / c 0 ) versus time, the rate constant ( k ) can be calculated ( c and c 0 represent the 4‐NP concentration at time t and 0, respectively).…”

“…Ni nanowires were prepared according to our previous work with some modification. [10] In at ypical process, CTAB (0.924 g) was dissolved in EG (48 mL) and stirred for 15 min at 323 K, followed by addition of NiCl 2 ·6H 2 O( 0.1098 g) with stirring for another 15 min. Over an interval of 15 min, NaOH (1 m, 4mL) and of N 2 H 4 ·H 2 O (0.8 mL) were added into the above solution.…”

Facile Fabrication of Well‐Dispersed Pt Nanoparticles in Mesoporous Silica with Large Open Spaces and Their Catalytic Applications

“…Considering excess NaBH 4 was used, pseudo-first-order kinetics could be applied for the evaluation of the rate constants. [33,34] Figure 5C shows the ln(C/C 0 )v ersus reaction time data for the reductiono f4 -NP over Pt@OMS and Pt/OMS. Al inear correlation is found between ln(C/C 0 )a nd the reaction time in each case and their corresponding rate constants k are calculated to be 0.53 and 0.22 min À1 ,r espectively.T he high catalytic activity of Pt@OMS could be attributed to the small size of Pt NPs and large open space of channels in Pt@OMS which allow fast molecule diffusion in the channels.…”

“…As observed in Figure A and B, the time for the complete reduction of 4‐NP over Pt@OMS was 7 min in the presence of NaBH 4 , which was shorter than the corresponding reduction time of Pt/OMS (16 min). Considering excess NaBH 4 was used, pseudo‐first‐order kinetics could be applied for the evaluation of the rate constants . Figure C shows the ln( C / C 0 ) versus reaction time data for the reduction of 4‐NP over Pt@OMS and Pt/OMS.…”