High specific surface area carbides and nitrides

Claim 1

A method for preparing high specific surface area molybdenum and vanadium carbides and nitrides from an oxide, said carbides and nitrides having at least a 5-fold increase in surface area over said oxide, which method comprises: in a first heating, heating said oxide to a temperature prior to significant reduction and formation of said carbide or nitride; in a second heating following said first heating, continuing heating of said oxide substantially uniformly and continuously at a rate in the range of about 0.1° to 5° K./min in the presence of a reducing environment and a source of carbon or nitrogen from a time at least 20 minutes prior to the time of completion of formation of said carbide or nitride and at a temperature at least 25° K. prior to substantial completion of formation of said carbide or nitride, and through a temperature range where reduction of said oxide and reaction with carbide and nitrogen occurs to form a carbide or nitride respectively, said heating continuing until said reaction is substantially complete as evidenced by the substantial absence of change in the effluent composition; and quenching the reaction by lowering the temperature within the lesser of about one hour or about 50 percent of the time of said second heating.

Claim 2

A method for preparing high specific surface area molybdenum and vanadium carbides and nitrides from an oxide, said carbides and nitrides having at least a 5-fold increase in surface area over said oxide, which method comprises: in a first heating, heating said oxide to a temperature prior to significant reduction and formation of said carbide or nitride; in a second heating following said first heating, continuing heating of said oxide substantially uniformly and continuously at a rate in the range of about 0.1° to 5° K./min in the presence of a reducing environment and a source of carbon or nitrogen from a time at least 20 minutes prior to the time of completion of formation of said carbide or nitride and at a temperature at least 25° K. prior to substantial completion of formation of said carbide or nitride, and through a temperature range where reduction of said oxide and reaction with carbide and nitrogen occurs to form a carbide or nitride respectively, said heating continuing until said reaction is substantially complete as evidenced by the substantial absence of change in the effluent composition; and quenching the reaction by lowering the temperature within the lesser of about one hour or about 50 percent of the time of said second heating.

Claim 6

A method for preparing a high specific surface area molybdenum or vanadium carbide from an oxide, said carbide having at least a 5-fold increase in surface area over said oxide, which method comprises: in a first heating, heating said oxide to a temperature prior to significant reduction and formation of said carbide; in a second heating following said first heating, continuing heating of said oxide substantially uniformly and continuously at a rate in the range of about 0.1° to 5° K./min in the presence of a reducing environment and a source of carbon from a time at least 20 minutes prior to the time of completion of formation of said carbide and at a temperature at least 25° K. prior to substantial completion of formation of said carbide, and through a temperature range where reduction of said oxide in reaction with carbon occurs to form a carbide, said heating continuing until said reaction is substantially complete as evidenced by the substantial absence of change in the effluent composition; and quenching the reaction by lowering the temperature within the lesser of about one hour or about 50 percent of the time of said second heating.

Claim 7

A method for preparing a high specific surface area molybdenum or vanadium carbide from an oxide, said carbide having at least a 5-fold increase in surface area over said oxide, which method comprises: in a first heating, heating said oxide to a temperature prior to significant reduction and formation of said carbide; in a second heating following said first heating, continuing heating of said oxide substantially uniformly and continuously at a rate in the range of about 0.1° to 5° K./min in the presence of a reducing environment and a source of carbon from a time at least 20 minutes prior to the time of completion of formation of said carbide and at a temperature at least 25° K. prior to substantial completion of formation of said carbide, and through a temperature range where reduction of said oxide in reaction with carbon occurs to form a carbide, said heating continuing until said reaction is substantially complete as evidenced by the substantial absence of change in the effluent composition; and quenching the reaction by lowering the temperature within the lesser of about one hour or about 50 percent of the time of said second heating.

Claim 11

A method for preparing high specific surface area molybdenum and vanadium nitrides from an oxide, said nitrides having at least a 5-fold increase in surface area over said oxide, which method comprises: in a first heating, heating said oxide to a temperature prior to significant reduction and formation of said nitride; in a second heating following said first heating, continuing heating of said oxide substantially uniformly and continuously at a rate in the range of about 0.1 to 5%/min in the presence of a gaseous source of hydrogen and nitrogen from a time at least 20 minutes prior to the time of completion of formation of said nitride and at a temperature at least 25° K. prior to substantial completion of formation of said nitride, and through a temperature range where reduction of said oxide in reaction with nitrogen occurs to form a nitride, said heating continuing until said reaction is substantially complete as evidenced by the substantial absence of change in the effluent composition; and quenching the reaction by lowering the temperature within the lesser of about one hour or about 50 percent of the time of said second heating.

Claim 12

A method for preparing high specific surface area molybdenum and vanadium nitrides from an oxide, said nitrides having at least a 5-fold increase in surface area over said oxide, which method comprises: in a first heating, heating said oxide to a temperature prior to significant reduction and formation of said nitride; in a second heating following said first heating, continuing heating of said oxide substantially uniformly and continuously at a rate in the range of about 0.1 to 5%/min in the presence of a gaseous source of hydrogen and nitrogen from a time at least 20 minutes prior to the time of completion of formation of said nitride and at a temperature at least 25° K. prior to substantial completion of formation of said nitride, and through a temperature range where reduction of said oxide in reaction with nitrogen occurs to form a nitride, said heating continuing until said reaction is substantially complete as evidenced by the substantial absence of change in the effluent composition; and quenching the reaction by lowering the temperature within the lesser of about one hour or about 50 percent of the time of said second heating.