The enhanced role of surface amination on the catalytic performance of polyacrylonitrile supported palladium nanoparticles in hydrogen generation from formic acid

Abstract

Hydrogen production by formic acid (FA) has attracted widespread attention in the field of catalysis and energy chemistry. Here, we develop a highly efficient catalyst for FA dehydrogenation by surface amination of polyacrylonitrile (PAN) supported palladium nanoparticles (Pd NPs). The support of PAN derived from a soap‐free emulsion polymerization was ammoniated by simply treating it with ethylenediamine (EDA) solution under heating. Compared with the parent PAN material, the aminated PAN (EDA‐PAN) is a more suitable support to achieve high dispersion of Pd NPs with ultra‐small particle size (around 1.2 nm), and to fabricate more active and stable supported Pd‐based catalyst for FA dehydrogenation. The turnover frequency (TOF) of the Pd/EDA‐PAN catalyst could reach to 3989 h−1 at 333 K without using any additional bases or additives. More significantly, the aminated catalyst could even work well at ambient temperature with a TOF of 688 h−1 at 303 K.

Bimetallic PdCo Nanoparticles Loaded in Amine Modified Polyacrylonitrile Hollow Spheres as Efficient Catalysts for Formic Acid Dehydrogenation

“…The TEM images of Pd/EDA-HPAN and PdCo 0.2 /EDA-HPAN show that a large number of ultra-small Pd-based NPs are uniformly dispersed on the surface of the EDA-HPAN (Figure 2). The Pd-based NPs observed in the region of the two images have an average diameter of about 0.88 nm and 0.81 nm, respectively, smaller than the previous reported EDA-PAN supported Pd NPs (1.2 nm) [41]. This might be mainly related to the fact that the HPAN support with hollow sphere structure has a rougher spherical surface and a higher specific surface area, as revealed by the following N 2 adsorption-desorption measurements, which can provide more space for the uniform distribution of the amino groups as well as the introduced metal NPs.…”

“…It can be inferred from the TEM image in Figure 2 that the amine groups introduced by amination should be uniformly distributed on the surface of EDA-HPAN. Combined with results of the N2 adsorption isotherms of HPAN and EDA-HPAN, the specific surface areas of the HPAN and EDA-HPAN supports calculated by the Brunauer-Emmett-Teller method are 45 and 48 m 2 /g, respectively (Table 1), which are higher than those of coral-like PAN and EDA-PAN reported in our previous work [41].…”

“…Previously, the authors and our coworkers also carried out some studies on the preparation of supported Pd-based NPs catalysts for FA dehydrogenation [41][42][43][44]. Interestingly, by using low-cost polymer materials such as polyacrylonitrile (PAN) and modified PAN as supports, relatively active supported Pd, Pd-Me (Me = Fe, Co, or Ni) NPs catalysts were obtained [41][42][43].…”

“…Previously, the authors and our coworkers also carried out some studies on the preparation of supported Pd-based NPs catalysts for FA dehydrogenation [41][42][43][44]. Interestingly, by using low-cost polymer materials such as polyacrylonitrile (PAN) and modified PAN as supports, relatively active supported Pd, Pd-Me (Me = Fe, Co, or Ni) NPs catalysts were obtained [41][42][43]. It was found that modification of PAN with a suitable amount of ethylenediamine could further improve the dispersity and stability of Pd NPs, thus resulting in formation of a highly active supported Pd catalyst with ultra-small particle size (abound 1.2 nm), which can work well for FA dehydrogenation with a TOF 688 h −1 at 303 K [41].…”

“…Interestingly, by using low-cost polymer materials such as polyacrylonitrile (PAN) and modified PAN as supports, relatively active supported Pd, Pd-Me (Me = Fe, Co, or Ni) NPs catalysts were obtained [41][42][43]. It was found that modification of PAN with a suitable amount of ethylenediamine could further improve the dispersity and stability of Pd NPs, thus resulting in formation of a highly active supported Pd catalyst with ultra-small particle size (abound 1.2 nm), which can work well for FA dehydrogenation with a TOF 688 h −1 at 303 K [41]. As a continuation of the above work, we here tried to use ethylenediamine modified PAN hollow nanospheres (HPAN) as support to prepare supported Pd and PdCo NPs catalysts.…”