Polystyrene seed was synthesized by using polyvinylpyrrolidone(PVPD), sodium dioctyl sulfosuccinate (Aerosol-OT), styrene, and azobis-iso-butylonitrile(AIBN). The polystyrene seed was coated with nickel nitrate solution. The optimal synthetic condition had the composition of 0.1 g of polystyrene seed, 0.65 g of polyvinylpyrrolidone, 54 g of urea, and 1.25 g of nickel nitrate, and they were reacted for 3 hrs at 90 ℃. Experimental parameters depended on reacting temperature, reacting time and concentration of starting materials. The hollow sphere nickel oxide was obtained by heat-treatment of coated polystyrene seed at 450℃.

Polyvinylpyrrolidone (PVPD), sodium dioctyl sulfosuccinate (Aerosol-OT), styrene, azobis-isobutylonitrile (AIBN) 등을 사용하여 polystyrene seed를 합성하였다. 이렇게 얻어진 seed를 nickel nitrate 용액속에서 코팅시켰다. 코팅 최적조건은 polystyrene seed 0.1 g, polyvinyl pyrrolidone 0.65 g, urea 54 g, nickel nitrate 1.25 g을 90 ℃ 반응온도에서 반응시간 3h 이었다. 실험 변수로는 반응온도, 반응시간, 출발물질의 농도를 변화시켰다. 코팅된 polystyrene seed를 450 ℃로 열처리하여 중공형 니켈산화물을 얻었다.