The economical preparation of carbon materials is also important for practical applications. Template materials investigated to date, such as nanostructured silica, 103,104 γ-ANP, θ-ANP, and zeolite, require the use of hazardous HF aqueous solutions for their removal after CVD, which makes the synthetic process tedious. For practical industrial applications, HF should be replaced with the less hazardous HCl. Catalytically active MgO 105-107 is a promising template material that does not require HF during template etching. Investigating the dissolution of ANPs and zeolites in benign and safe ways is crucial for the practical application of NPGs.