As well as their chemical binding in nitrocellulose and nitroglycerin ("nitro. . ." is due to the presence of nitrogen). I burn - oxidize - nitrogen every day and titanium has nothing to do with it, nitrogen oxides are produced in the internal combustion engines in my vehicles, and more is produced in the catalytic converters of those vehicles. Platinum, in a finely dispersed form on alumina oxide substrate has been a standard in catalytic converters. But platinum has largely been replaced with other transition metals from the periodic table of elements such as palladium that, like platinum, catalyze oxidation of remaining uncombusted hydrocarbons and carbon monoxide toward carbon dioxide without catalyzing oxidation of atmospheric diatomic nitrogen, N2, to oxides of nitrogen such as NO, NO2, etc. the environmental folks lump into one category called NOX, where the X represents a non zero positive integer, also defined as a counting number, such as 1 or 2. There's some NOX formed from oxidation - combustion - of atmospheric diatomic nitrogen in the combustion chambers of my internal combustion engines as well. Designers have worked to minimize this in a number of ways including exhaust gas recirculation EGR to lower flame peak temperatures and "ultra lean burn" mixtures, nearly stoichiometric with respect to the ratio of amount of oxygen to hydrocarbon fuel sent via the intake system of the engine. Multiple spark plugs per cylinder (combustion chamber) is used in some engine designs to address trying to strike the best balance between efficiency in the combustion of the hydrocarbon fuel vs thermal NOX production in the combustion chamber. The 5.7L "Hemi" V8 engine in my 2012 Ram truck is one such design with 16 spark plugs, each with its own ignition coil in the now common coil on plug configuration. No titanium is involved in this either. There's iridium involved because I replaced the factory conventional spark plugs with iridium tipped spark plugs at the first such recommended interval because there's limited access to a number of these spark plugs - the one below the power brake vacuum diaphragm next to the firewall is a prime example. The iridium has nothing to do with thermal NOX production, simply spark plug tip and gap life.
I have a nice 9 lb Boston Butt pork roast going on one of my patio size smoker for an extended spa treatment with combustion products, including CO2, CO, NOX, and others from the hardwood charcoal and hardwood smoke wood fuel I'm using for that. No catalyst involved, no titanium, negligible "feed NOX" - oxides of nitrogen produced from nitrogen chemically present in the fuel - unlike say Kingsford "classic" charcoal that includes anthracite and lignite (sub-bituminous) mineral coal - mined solid fossil fuel - as well as sodium nitrate (also a component in black powder) as an ignition aid for those mineral coal components. Folks with electric smokers aren't able to get much, if any, of a pink smoke ring from electric element heat and wood chips, some augment this by laying a few briquettes of classic Kingsford charcoal up against the electric heating element over the course of a cook session. I don't grill or smoke foods with fuels containing mineral coal, personal choice, and I obtain distinctive smoke rings from the exposure of the meat to the thermal NOX in the smoke chamber. Chemical nitrate salts used as antimicrobial agents present in typical hams, bacon (including Canadian bacon), pastrami, and others in the category of "cured meats".
Smokeless powder combustion produces a lot of "feed NOX" from all the nitrogen chemically present in the nitrocellulose (and nitroglycerin for double base) present, as well as some thermal NOX due to the combustion flame temperature with atmospheric diatomic nitrogen N2 present in about a 4:1 ratio with oxygen in the ambient air along with the smokeless powder in the cartridge case. Black powder combustion similarly produces both fuel NOX from the potassium nitrate component and thermal NOX from the diatomic nitrogen present in the ambient air used as the source of oxygen for the combustion reaction. With my firearms, there's no titanium involved in this.
A peek at a chemical formula for nitrocellulose shows the chemical nitrogen present from reaction with nitric acid, HNO3. The reaction formula is present along with chemical formulae and molecular structures of nitrocellulose on Wikipedia for one such spot.
en.m.wikipedia.org
Similar with nitroglycerin
en.m.wikipedia.org
And NOX, with discussion of sources, thermal NOX vs fuel NOX.
en.m.wikipedia.org
Twenty years ago I was involved in studies at the end user point for reducing NOX (& SOX) emissions from an extremely important process used in petroleum refining, Fluid Catalytic Cracking, through additives in the catalyst vs separate chemical reactor systems. No titanium is involved in these additives. That became a significant market segment for companies to produce and manufacture these additives for refiners that operate in places like the USA & Western Europe as an alternative operating cost route easily implemented vs capital investments in construction projects that take years to execute, and as regulations change, become obsolete.
This is one such company
So, while some think of diatomic nitrogen gas as relatively inert, it's not as inert as the monoatomic molecular structure noble gases with full outer electron "shell" orbitals. When chemical compounds are made from such elements they're also not very stable. Xenon trifluoride is one but it's more a curiosity than say nitrocellulose and nitroglycerin.
en.m.wikipedia.org
