A method of producing an sp3 bonded C 3 N 4 product, the method comprising: contacting a starting material with a catalyst solvent in a reaction vessel, wherein the starting material comprises sp2 bonded C 3 N 4 and the catalyst solvent is solid at room temperature; heating the reaction vessel to a temperature of 900° to 2000°C under a pressure of 4 to 8 GPa; melting at least some of the catalyst solvent; transforming at least some of the sp2 bonded C 3 N 4 into sp3 hybridized C 3 N 4; wherein the catalyst solvent is a carbo-nitride based catalyst solvent comprising: a first compound, the first compound having the chemical formula: A x B y N z wherein A is selected from the group consisting of the transition metals, lanthanide metals and Ca; wherein B is selected from the group consisting of the Group IIIB metalloid elements, the Group IVB metalloid elements, Mg, Zn, and Cd; wherein N is nitrogen; wherein x is from 2.5 to 3.5; wherein y is from 0.5 to 1.5; wherein z is from 0.5 to 1.5; and a second compound, the second compound having the chemical formula: D q E r C s wherein D is selected from the group consisting of the transition metals, lanthanide metals and Ca; wherein E is selected from the group consisting of the Group IIIB metalloid elements, the Group IVB metalloid elements, Mg, Zn, and Cd; wherein C is carbon; wherein q is from 2.5 to 3.5; wherein r is from 0.5 to 1.5; wherein s is from 0.5 to 1.5; wherein the stoichiometric ratio of the number of moles of carbon of the second compound to the number of moles of nitrogen of the first compound in the catalyst solvent is from 2.5:4 to 3.9:4. contacting a starting material with a catalyst solvent in a reaction vessel, wherein the starting material comprises sp2 bonded C 3 N 4 and the catalyst solvent is solid at room temperature; heating the reaction vessel to a temperature of 900° to 2000°C under a pressure of 4 to 8 GPa; melting at least some of the catalyst solvent; transforming at least some of the sp2 bonded C 3 N 4 into sp3 hybridized C 3 N 4; wherein the catalyst solvent is a carbo-nitride based catalyst solvent comprising: a first compound, the first compound having the chemical formula: A x B y N z wherein A is selected from the group consisting of the transition metals, lanthanide metals and Ca; wherein B is selected from the group consisting of the Group IIIB metalloid elements, the Group IVB metalloid elements, Mg, Zn, and Cd; wherein N is nitrogen; wherein x is from 2.5 to 3.5; wherein y is from 0.5 to 1.5; wherein z is from 0.5 to 1.5; and a second compound, the second compound having the chemical formula: D q E r C s wherein D is selected from the group consisting of the transition metals, lanthanide metals and Ca; wherein E is selected from the group consisting of the Group IIIB metalloid elements, the Group IVB metalloid elements, Mg, Zn, and Cd; wherein C is carbon; wherein q is from 2.5 to 3.5; wherein r is from 0.5 to 1.5; wherein s is from 0.5 to 1.5; wherein the stoichiometric ratio of the number of moles of carbon of the second compound to the number of moles of nitrogen of the first compound in the catalyst solvent is from 2.5:4 to 3.9:4. a first compound, the first compound having the chemical formula: A x B y N z wherein A is selected from the group consisting of the transition metals, lanthanide metals and Ca; wherein B is selected from the group consisting of the Group IIIB metalloid elements, the Group IVB metalloid elements, Mg, Zn, and Cd; wherein N is nitrogen; wherein x is from 2.5 to 3.5; wherein y is from 0.5 to 1.5; wherein z is from 0.5 to 1.5; and a second compound, the second compound having the chemical formula: D q E r C s wherein D is selected from the group consisting of the transition metals, lanthanide metals and Ca; wherein E is selected from the group consisting of the Group IIIB metalloid elements, the Group IVB metalloid elements, Mg, Zn, and Cd; wherein C is carbon; wherein q is from 2.5 to 3.5; wherein r is from 0.5 to 1.5; wherein s is from 0.5 to 1.5; wherein the stoichiometric ratio of the number of moles of carbon of the second compound to the number of moles of nitrogen of the first compound in the catalyst solvent is from 2.5:4 to 3.9:4.