A model for the responses of Nb2O5 sensors to CO and NH3 gases

One-Pot Electrochemical Synthesis of Hierarchical Porous Niobium

“…Under these assumptions, the area of the pores in the n th hierarchical order can be calculated by the following mathematical equations. After the initial pore formation process, N 1 , the number of pores with n = 1 (primary pores), can be evaluated as (2) where S 0 is the initial surface area of the material and r 1 is the radius of the primary pores. Thus, the surface area of the primary pores with a presumed oblate spheroidal shape, A oblate,1 , is ,…”

“…Because of its variable oxidation states, Nb, a transition metal, can react with various elements such as oxygen, carbon, and nitrogen to form a wide range of functional compounds. One such compound is Nb 2 O 5 , which has received significant attention as an electrode material for sensors [1][2][3][4], dye-sensitized solar cells [5], photodetectors [6], and capacitors [7,8], because of its large band-gap (3.2~4 eV) [9] and high dielectric constant (~41) [10]. Moreover, it can be applied as an electrode material in lithium secondary batteries because of its excellent energy storage per unit volume as well as its suitable charge and discharge potentials [11,12].…”

Nanoporous Nb2O5 hydrogen gas sensor

“…There are many reports on the gas sensing properties of nanostructured metal oxides such as SnO 2 , ZnO, TiO 2 , WO 3 , In 2 O 3 , CuO, NiO, Ga 2 O 3 , and V 2 O 5 [5][6][7][8][9][10][11][12][13][14]. However, a much smaller number of papers address the feasibility of Nb 2 O 5 for gas sensing [15][16][17][18][19][20][21][22][23][24]. Nb 2 O 5 is known as a wide band-gap n-type metal oxide and has desirable properties such as good chemical stability, low film stress, and a high refractive index (n = 2.4 at 550 nm) [25].…”

“…The first report on Nb 2 O 5 gas sensors dates back to the early 1980s [15]. However, comprehensive reports on Nb 2 O 5 mostly belong to the mid to late 1990s [16][17][18][19]. In these works, techniques such as radio frequency magnetron sputtering were used for the deposition of dense Nb 2 O 5 films and operating temperatures as high as 500 ºC were implemented to sense gases such as O 2 , NH 3 and CO. Porous Nb 2 O 5 films for gas sensing were later reported.…”

Etching of Nb2O5 Thin Films by NbCl5

“…k ¼ 4 for SiO 2 ) with potential thin film applications in integrated storage capacitors in, e.g., dynamic random access memory (DRAM) devices, [2][3][4][5] conductivity-type sensors for gases such as oxygen, [6,7] water, [8] and ammonia, [9] optical waveguides in laser light sources, [10,11] corrosion-resistant coatings, [12] and electrochromic devices. [13,14] Nb 2 O 5 is also a frequently used constituent of multicomponent oxides and solid solutions such as LiNbO 3 , [15] (Nb 1Àx Ta x ) 2 O 5 , [16] BaTi 1þ2n Nb 4 O 13þ4n , [17] [18] and dopant in various oxides such as ZrO 2 , [19] SnO 2 , [20] (Zr 0.8 Sn 0.2 )TiO 4 , [21,22] Pb(Zr 0.52 Ti 0.48 )O 3 , [23,24] and ZrO 2 Á 3Y 2 O 3 .…”