Nanodispersed diamond

Abstract. The object of this work was to investigate hydrogen oxidation and oxygen reduction from surface of modified nanodispersed diamond. The catalytic reactions on the surface of nanodispersed diamond have been studied after different treatment using heat-treated and electrochemical methods. 

For developing the modifying of nanodispersed diamond there have been proposed the following treatment ... 

It has been established that special heat-treated treatment to surface of nanodispersed diamond effective for hydrogen electrode material creation. 

Precipication of palladium of nanodispersed diamond surface it to be saturated with atomic oxygen. The quantity of atomic oxygen is higher than that of molecular oxygen. 

It has been shown that nanodispersed diamond, after precipication of palladium are effective catalyst of oxygen reduction. 

Keywords Hydrogen oxidation, oxygen reduction, nanodispersed diamond, surface, heat-treated treatment, hydrogen electrode, oxygen electrode. 

Figure 3 compares the exchange current densities on the initial nanodispersed diamond (4), modified nanodispersed diamond (after heat - treated treatment)(5), acetylene black AD-100 (1) and on the known catalysts tungsten (2) and vanadium (3) carbides. The specific surfaces of all samples of the powders were about 140 rrr/g. The exchange current density on modified diamond nanopowders is higher than that on tungsten or vanadium carbides by a factor of 1.6. 

The cathode potentiodynamic curves of electroreduction of oxygen from the surface of the initial nanodispersed diamond (1) and initial nanodispersed diamond after precipitation of palladium (2) were presented. (Fig. 4). It is shown, that electrode catalitic activity precipication palladium electrode increased into 1,5— 2,0. Specific activity with romoted palladium nanodispersed diamond is equal to value 1.0 A/g to active weight. 

Figure 4. The cathode potentiodynamic curves of electroreduction of oxygen from the surface of the initial nanodispersed diamond(l) and initial nanodispersed diamond ffter precipitation of...

The kinetic of catalytic oxygen reduction is closely connected with chemical condition of surface nanodispersed diamond. 

Figure 6. The exchange current density of oxygen electroreduction from acetylene black AD-100(1), initial nanodispersed diamond(2), diamond ASM 1/0,5(3), initial nanodispersed diamond after palladium presipitation (4).

Figure 7. Thermodesorption spectra of water from the surface the initial nanodispersed diamond (1), the diamond after promouted palladium(2).

Bogatyreva G.P., Marinich M.A. (2004) Modification of submicronic and nanodispersed diamonds. Proc. Synthesis, Properties and Applications of ultra nanocristaline Diamond , 43. 

---