Tetraammineplatinum(II) and Tetraamminepalladium(II) Chromates as Precursors of Metal Oxide Catalysts

Abstract

[M(NH3)4]A (M=Pt, Pd; A=CrO4, Cr2O7) and [Pt(NH3)4(NO2)(Cr2O7)]NO3 complex salts were synthesized and characterized by a number of physicochemical methods of analysis (IR, single‐crystal and powder XRD, and simultaneous thermogravimetry and differential scanning calorimetry with evolved gas analysis mass spectrometry). Thermolysis of the salts obtained in a hydrogen atmosphere proceeds with the partial reduction of chromium to a metallic state and the formation of MxCr1−x (M=Pt, Pd) metal solid solution with a chromium content of up to 22 at % and chromium(III) oxide. The thermal decomposition of salts in an inert and oxidizing atmosphere passes through the formation stage of the MCrO2 phase with the delafossite structure followed by its subsequent decomposition into chromium(III) oxide and noble metal. Nanosized Pt−Cr2O3 and Pd−Cr2O3 composites obtained by the thermolysis of precursor salts in air at 500 °C and being held at this temperature for 1 h showed a high catalytic activity in the CO total oxidation (TOX) and preferential oxidation in the excess of hydrogen (PROX) processes compared with that of monometallic Pt and Pd powders.

On-Line Thermally Induced Evolved Gas Analysis: An Update—Part 1: EGA-MS

“…The results showed that larger pore volume and higher active metal dispersion were obtained in comparison with the sample calcinated in air [ 78 ]. Tetraammineplatinum(II) and tetraamminepalladium(II) chromates as precursors of metal oxide catalysts were reported by Filatov et al [ 79 ].…”

Synthesis and investigation of the thermal properties of [Co(NH3)6][Co(C2O4)3]·3H2O and [Ir(NH3)6][Ir(C2O4)3]

“…Nanosized bimetallic compounds (including solid solutions and nanocomposite materials) are of great interest for science and industry. The presence of two metals at the same time can lead to a mutual enhancement of the properties (synergism) of metal particles, while the increased ratio of the atoms on the surface and in the volume and small size of nanosystems make them more advantageous in comparison with the monometallic analogues (Filatov et al, 2020;Potemkin et al, 2018Potemkin et al, , 2019. Nanoalloys can have high catalytic activity (Potemkin et al, 2018;Jin et al, 2019), as well as having electrically conductive (Hu et al, 2019) and magnetic properties (Abel et al, 2019).…”

“…by changing the ratio of the metals in the initial compound, the ratio of the metals in the resulting nanoalloy can be varied. In addition, mixing metals at the molecular level makes it possible to obtain bimetallic nanosystems at low decomposition temperatures and, in many cases, synthesize metastable multi-metal systems that cannot be obtained by mixing two starting compounds containing the required metals and calcining them under the same conditions (Filatov et al, 2020;Kahani & Shahrokh, 2015;Zadesenets et al, 2018Zadesenets et al, , 2019Korenev et al, 2003).…”

Platinum Based Nanoparticles Produced by a Pulsed Spark Discharge as a Promising Material for Gas Sensors

“…In this case, the formation of platinum nanoparticles is carried out by incipient wetness impregnation of a porous support, such as CeO 2 or γ-Al 2 O 3 , with an aqueous solution of this precursor, followed by drying and calcination at a temperature of 500 • C [19]. Tetraammineplatinum(II) chromates were also reported as precursors of Pt-Cr 2 O 3 composite catalysts, obtained by the thermal decomposition of these complex salts [20]. Since the application of chemical methods implies concerns about biosafety, methods based on the green chemistry approach are getting popular.…”