Nanobubbles: An Effective Way to Study Gas-Generating Catalysis on a Single Nanoparticle

Abstract

Gas-generating catalysis is important to many energy-related research fields, such as photocatalytic water splitting, water electrolysis, etc. The technique of single-nanoparticle catalysis is an effective way to search for highly active nanocatalysts and elucidate the reaction mechanism. However, gas-generating catalysis remains difficult to investigate at the single-nanoparticle level because product gases, such as H and O, are difficult to detect on an individual nanoparticle. Here, we successfully find that nanobubbles can be used to study the gas-generating catalysis, i.e., H generation from formic acid dehydrogenation on a single Pd-Ag nanoplate, with a high time resolution (50 ms) via dark-field microscopy. The research reveals that the nanobubble evolution process includes nucleation time and lifetime. The nucleation rate of nanobubbles is proportional to the catalytic activity of a single nanocatalyst. The relationship between the catalytic activity and the nucleation rate is quantitatively described by a mathematical model, which shows that an onset reaction rate (r) exists for the generation of nanobubbles on a single Pd-Ag nanoplate. The research also reveals that a Pd-Ag nanoplate with larger size usually has a higher activity. However, some large-sized ones still have low activities, indicating the size of the Pd-Ag nanoplate is not the only key factor for the activity. Notablely, further research shows that Pd content is the key factor for the activity of single Pd-Ag nanoplates with similar size. The methodology and knowledge acquired from this research are also applicable to other important gas-generating catalysis reactions at the single-nanoparticle level.

Hollow polymer dots: nature-mimicking architecture for efficient photocatalytic hydrogen evolution reaction

“…Detailed hydrogen bubble formation in the hollow polymer vesicles is unclear since there are only few theoretical studies about nanobubble nucleation and formation for nanochannels or nanospaces. [49][50][51] Although there is a high possibility that nanobubbles might be generated on Pdots with the assistance of remaining free amphiphilic surfactant in solution, 52 Pdot photocatalysts can be reactivated for hydrogen generation by degassing the system with Ar. This proves that the deactivation process is actually caused by generated hydrogen.…”

Spatiotemporal Heterogeneity of Reactions in Solution Observed with High‐Speed Single‐Nanorod Rotational Sensing

“…With DFM, Li et al reported previously that the formation of surface nanobubbles leads to at ime-dependent scattering intensity change of the single NP catalyst. [13] Here,with HSLDFM and the rotation sensing of asingle AuNR, we monitored the Pt-catalyzed decomposition of H 2 O 2 .W eu sed 40 nm 96 nm AuNR@PtNDs (Nanoseedz), where the AuNR surface is decorated by 3nmP t nanodots.T ransmission electron microscopy (TEM) results indicated that the NRs are monodisperse and uniform in size. UV/Vis spectroscopy showed their extinction maximum is at % 740 nm.…”

Surface interaction between Pd and nitrogen derived from hyperbranched polyamide towards highly effective formic acid dehydrogenation

“…It is hard to reuse and recycle the catalysts for the whole reaction. Compared to the homogeneous catalysts, the heterogeneous catalysts are easy for reusing and recycling and are friendly to the environments [16][17][18][19] . The noble metal based heterogeneous catalysts have been proven active in producing hydrogen from FAD under mild conditions, among which Pd based heterogeneous catalyst are found especially effective.…”