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Currently, energy demand is growing swiftly with global economic growth. The combustion of fossil fuels is one of the major environmental threats due to the release of CO2 into the atmosphere. Reducing greenhouse gases is one of the most critical challenges facing society today. It has been proposed that converting CO2 into fuels and valuable chemicals such as methanol for reducing greenhouse gas emissions can be a favorable solution. This review describes the recent development of methanol synthesis from CO2 from a mechanistic point of view. Several proposed reaction pathways for methanol formation over various catalysts will be emphasized, i.e., Cu-based catalyst, precious metal-based catalyst, and other catalysts, including oxide-, oxygen deficient-, and composite-based catalysts such as metal alloys, and supported metal alloys. Additionally, the intermediate involved, active site, and several aspects affecting the catalytic behavior are also provided. Finally, a remaining challenge and the perspective for compelling the energy future vision is emphasized.

SrTiO3 bulat berongga yang tersusun dari nano kubus telah disintesis dengan penambahan cetyltrimethylammonium bromide (CTAB) sebagai capping agent untuk mengontrol morfologi partikel. Kondisi sintesis pada suhu 220 °C selama 48 jam dengan perbandingan mol Sr:Ti = 1:1.25 dan perbandingan material awal dengan CTAB adalah 1:0.5 menghasilkan partikel dengan kristalinitas yang tinggi pada puncak spesifik 2θ = 32.41o bidang 110 yang merujuk pada struktur perovskit kubus. Penghalusan struktur kristal dengan metoda Rietveld menunjukkan bahwa struktur kristal hasil pengukuran memiliki kecocokan yang tinggi dengan hasil perhitungan dengan nilai Rwp adalah 12.07. Interaksi antara CTAB dan permukaan SrTiO3 terlacak pada spektrum FTIR dengan angka gelombang 1100-1250 cm-1 membuktikan adanya vibrasi ulur C-N yang melemah akibat proses capping. Foto SEM menunjukkan bahwa partikel yang terbentuk umumnya memiliki bentuk bulat berongga, sementara foto TEM memperlihatkan partikel berongga berukuran mikro dibentuk dari susunan nanokubus berukuran rata-rata 20 nm. Kata kunci: Capping agent, partikel berongga, nanokubus, solvotermal, perovskite The synthesis of SrTiO3 hollow sphere built as assembly of nanocubes using cetyltrimethylammonium bromide (CTAB) as capping agent was aimed to control the size and shape of the particles. The condition of the synthesis at 220 °C for 48 hours with a molar ratio of Sr:Ti was 1:1.25 and starting material:CTAB was 1:0.5, have resulted the particles with a high crystallinity with specific XRD peaks at 2θ; 32.41 (110), which was in agreement with the cube-perovskite structure. The refinement of the crystal structure by the Rietveld method showed that the crystal structure of the measurement results has a high match with the result of the calculation with Rwp value was 12.07. The interaction between CTAB and the surface of SrTiO3 traced in the FTIR spectrum with wave number 1100-1250 cm-1 indicated the stretching vibration of C-N was weakened due to the capping process. SEM images showed the particles with hollow microsphere, while TEM images revealed that the hollow particles were assembled by nanocubes with an average size of 20 nm. Keywords: Capping agent, hollow, nanocube, solvothermal, perovskite.